PIMCO California Flexible Municipal Income Fund 424B3 Prospectus supplement

PIMCO California Flexible Municipal Income

Fund

Prospectus

April 30, 2023

(as supplemented January

12, 2024)

PIMCO California Flexible Municipal Income Fund

	Common Shares
	Institutional Class	Class A-1	Class A-2	Class A-3	Class A-4
PIMCO California Flexible Municipal Income Fund	CAFLX	CAFMX	CAFNX	CAFOX	CAFPX

Neither the U.S. Securities and Exchange Commission nor the U.S. Commodity

Futures Trading Commission has approved or disapproved of these securities or

determined that this prospectus is truthful or complete. Any representation to

the contrary is a criminal offense.

The Fund.

PIMCO California Flexible Municipal Income Fund (the “Fund”) is a newly

organized, non-diversified, closed-end management investment company that continuously

offers its shares of beneficial interest, par value of $0.00001 per share (the “Common

Shares”), and is operated as an “interval fund.” The Fund currently has five separate classes

of Common Shares: Institutional Class, Class A-1, Class A-2, Class A-3 and Class A-4.

Investment Objectives.

The Fund seeks to provide high current income exempt from federal

and California income tax. Capital appreciation is a secondary objective.

Investment Strategy.

The Fund attempts to achieve these objectives by investing, under

normal circumstances, at least 80% of its net assets (plus any borrowings for investment

purposes) in a portfolio of municipal bonds and other municipal securities, the interest from

which, in the opinion of bond counsel for the issuer at the time of issuance (or on the basis of

other authority believed by Pacific Investment Management Company LLC (“PIMCO” or the

“Investment Manager”) to be reliable), is exempt from federal income tax and California

income tax (i.e., excluded from gross income for income tax purposes but not necessarily

exempt from the alternative minimum tax or from the income taxes of any other state or of a

local government) (the “80% policy”). To a lesser extent, the Fund also expects to invest in a

full range of preferred securities with an emphasis on preferred securities that, at the time of

issuance, are eligible to pay dividends that qualify for certain favorable federal income tax

treatment.

Portfolio Contents.

California municipal bonds generally are issued by or on behalf of the

State of California and its political subdivisions, financing authorities and their agencies. By

concentrating its investments in California municipal securities, the Fund will be subject to

California State-Specific Risk, among other risks. Both within and outside the 80% policy, the

Fund may invest in debt securities of an issuer located outside of California. The Fund's 80%

policy is a fundamental policy, which may not be changed without the approval of the holders

of a majority of the Fund's outstanding Common Shares and Preferred Shares (as defined

below) voting together as a single class, and of the holders of a majority of the outstanding

Preferred Shares voting as a separate class.

The Fund may invest without limit in municipal bonds and other securities that are rated below investment grade (or unrated but determined by

PIMCO to be of comparable quality). Bonds of below investment grade quality are regarded as having predominantly speculative characteristics

with respect to capacity to pay interest and repay principal and are commonly referred to as “junk bonds.” The Fund may also invest without limit

in investment grade securities.

Included within the general category of municipal bonds in which the Fund may invest are loans (including participations and assignments) and

participations in lease obligations.

The Fund may invest in and/or originate loans, including, without limitation, to, on behalf of, authorized by, sponsored by, and/or in connection

with a project for which authority and responsibility lies with one or more U.S. states or territories, cities in a U.S. state or territory, or political

subdivisions, agencies, authorities or instrumentalities of such states, territories or cities, which may be in the form of whole loans, assignments,

participations, secured and unsecured notes, senior and second lien loans, mezzanine loans, bridge loans or similar investments, including to

borrowers that are unrated or have credit ratings that are determined by one or more nationally recognized statistical rating organizations and/or

PIMCO to be below investment grade.

In addition to other types of securities and assets described in this section, the Fund may invest the balance of its assets (i.e., not towards its

80% policy noted above) in securities and assets that produce taxable income. Such assets are normally expected to include, but are not limited

to, preferred securities, with an emphasis on preferred securities that, at the time of issuance, are eligible to pay dividends that qualify for certain

favorable federal income tax treatment, such as dividends that are treated as qualified dividend income and eligible for the dividends received

deduction (in each instance, provided certain requirements and holding periods are satisfied).

It is possible that the Fund could own no preferred securities at any given time, including, for example, if municipal securities are expected to

produce a higher yield than preferred securities on an after-tax basis.

Subject to the Fund's investment policies described above, the Fund may invest in other securities, including commercial paper, securities eligible

for resale under Rule 144A of the Securities Act of 1933, as amended (the “1933 Act”), and other privately placed securities, and other debt

securities subject to federal and/or California income tax, including privately negotiated debt obligations with respect to which the principal and/or

interest is determined by reference to the performance of a benchmark asset, market or interest rate (an “embedded index”), such as specific

securities, an index of securities or specified interest rates, or the differential performance of two assets or markets, such as indexes reflecting

bonds. The rate of interest on an income-producing security may be fixed, floating or variable. The Fund may also engage in credit spread trades.

A credit spread trade is an investment position relating to a difference in the prices or interest rates of two bonds or other securities, in which the

value of the investment position is determined by changes in the difference between the prices or interest rates, as the case may be, of the

respective securities. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis and may

engage in short sales. The Fund may invest in trust certificates issued in tender option bond programs. In these programs, a trust typically issues

two classes of certificates and uses the proceeds to purchase municipal securities having relatively long maturities and bearing interest at a fixed

interest rate substantially higher than prevailing short-term tax-exempt rates. The Fund may also invest up to 5% of its total assets in securities of

other investment companies (including those advised by PIMCO), including closed-end funds, exchange-traded funds and other open-end funds,

that invest primarily in municipal bonds and other municipal securities of the types in which the Fund may invest directly.

The Fund may, but is not required to, invest in derivative instruments, such as options, futures or forward contracts or swap agreements. For

purposes of the Fund's 80% policy, the Fund values its derivative instruments based on their market value. The Fund may, without limitation, seek

to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other

investment techniques (such as buy backs or dollar rolls).

To the extent consistent with the applicable liquidity requirements for interval funds under Rule 23c-3 of the Investment Company Act of 1940, as

amended, the Fund may invest without limit in illiquid investments.

Interval Fund/Repurchase Offers.

The Fund is an “interval fund,” a type of fund which, in order to provide liquidity to shareholders, has adopted

a fundamental investment policy to make quarterly offers to repurchase between 5% and 25% of its outstanding Common Shares at net asset

value. Subject to applicable law and approval of the Fund's Board of Trustees, for each quarterly repurchase offer, the Fund currently expects to

offer to repurchase 10% of the Fund's outstanding Common Shares at net asset value.

Leverage.

The Fund currently utilizes leverage through its outstanding Remarketable Variable Rate MuniFund Term Preferred Shares (“RVMTP

Shares” and, together with any other preferred shares the Fund may have outstanding, “Preferred Shares”). The Fund may also choose to add

leverage through the use of tender option bonds, the issuance of additional Preferred Shares or the use of reverse repurchase agreements,

selling credit default swaps, dollar rolls/buy backs or borrowings, such as through bank loans or commercial paper and/or other credit facilities.

The Fund may issue additional Preferred Shares without the approval of holders of Common Shares (“Common Shareholders”). If the Fund

issues additional Preferred Shares in the future, all costs and expenses relating to the issuance and ongoing maintenance of the Preferred

Shares will be borne by the Common Shareholders, and these costs and expenses may be significant. Leveraging transactions pursued by the

Fund may increase its duration and sensitivity to interest rate movements. The Fund may also enter into transactions other than those noted

above that may give rise to a form of leverage including, among others, futures and forward contracts (including foreign currency exchange

contracts), total return swaps and other derivative transactions, loans of portfolio securities, short sales and when-issued, delayed delivery and

forward commitment transactions. The Fund may utilize certain kinds of leverage, including, without limitation, tender option bonds,

opportunistically and may choose to increase or decrease, or eliminate entirely, its use of leverage over time and from time to time based on

PIMCO's assessment of the yield curve environment, interest rate trends, market conditions and other factors. The Fund may also determine to

increase its leverage through the issuance of

additional

Preferred Shares

decrease the leverage

currently

maintains through

its

outstanding

Preferred Shares through

Preferred Share

redemptions or tender offers

and

may or may not determine to replace

such

leverage

through other

sources. By using leverage, the Fund seeks to obtain a higher return for Common Shareholders than if the Fund did not use leverage. Leveraging

is a speculative technique and there are special risks and costs involved. There can be no assurance that a leveraging strategy will be used or

that it will be successful during any period in which it is employed.

Investment Manager.

The Fund’s investment manager is Pacific Investment Management Company LLC. As of December 31, 2022, PIMCO

had approximately $1.74 trillion in assets under management.

◾

The Fund’s Common Shares are not listed for trading on any national securities exchange. The Fund’s Common Shares

have no trading market and no market is expected to develop.

◾

An investment in the Fund is not suitable for investors who need certainty about their ability to access all of the money

they invest in the short term.

◾

Even though the Fund will make periodic repurchase offers for its outstanding Common Shares, subject to the

limitations described herein, investors should consider Common Shares of the Fund to be an illiquid investment.

◾

There is no guarantee that you will be able to sell your Common Shares at any given time or in the quantity that you

desire.

◾

There is no assurance that the Fund will be able to make any distributions or maintain a certain level of distributions to

Common Shareholders.

Institutional Class, Class A-1, Class A-2, Class A-3 and Class A-4 Common Shares are offered in this prospectus. Each share class represents

an investment in the same portfolio of investments, but each class has its own expense structure and arrangements for shareholder services or

distribution, which allows you to choose the class that best fits your situation and eligibility requirements. Class A-1, Class A-2, Class A-3 and

Class A-4 Common Shares are primarily offered and sold to retail investors by certain broker-dealers that are members of the Financial Industry

Regulatory Authority and that have agreements with PIMCO Investments LLC, the Fund's principal underwriter and distributor, to sell Class A-1,

Class A-2, Class A-3 and/or Class A-4 Common Shares, but may be made available through other financial firms, including banks and trust

companies and to specified benefit plans. Only certain investors are eligible to purchase Institutional Class Common Shares. See “Plan of

Distribution – Share Classes.”

Institutional Class

The minimum initial investment for Institutional Class Common Shares is $1 million per account, except that the minimum investment may be

modified for certain financial firms that submit orders on behalf of their customers, the Trustees and certain employees and their extended family

members of PIMCO and its affiliates. There is no minimum subsequent investment amount. See “Plan of Distribution – Share Classes.”

Class A-1, Class A-2, Class A-3 and Class A-4

The minimum initial investment for Class A-1, Class A-2, Class A-3 and Class A-4 Common Shares is $2,500 per account, except that the

minimum investment may be modified for certain financial firms that submit orders on behalf of their customers, the Trustees and certain

employees and their extended family members of PIMCO and its affiliates. The minimum subsequent investment amount for Class A-1,

Class A-2, Class A-3 and Class A-4 Common Shares is $50. See “Plan of Distribution – Purchasing Shares.”

Investors should carefully consider the Fund’s risks and investment objectives, as an investment in the Fund may not be appropriate

for all investors and is not designed to be a complete investment program.

Before buying any of the Fund’s Common Shares, you should read the discussion of the principal risks of investing in the Fund in

“Principal Risks of the Fund” beginning on page

of this prospectus. No assurance can be given that the Fund’s investment

objectives will be achieved, and you could lose all of your investment in the Fund.

The Fund’s Common Shares do not represent a deposit or obligation of, and are not guaranteed or endorsed by, any bank or other insured

depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other

government agency.

Please read this prospectus carefully before deciding whether to invest and retain it for future reference. It sets forth concisely the information

about the Fund that a prospective investor ought to know before investing in the Fund. The Fund has filed with the Securities and Exchange

Commission (“SEC”) a Statement of Additional Information dated April 30, 2023, as

supplemented from time to time, containing additional

information about the Fund (the “Statement of Additional Information”). The Statement of Additional Information is incorporated by reference into

this prospectus, which means it is part of this prospectus for legal purposes. The Fund also produces both annual and semi-annual reports that

will contain important information about the Fund. Copies of the Statement of Additional Information and the Fund’s annual and semi-annual

reports, when available, may be obtained upon request, without charge, by calling 844.312.2113 or by writing to the Fund at Regulatory

Document Request, 650 Newport Center Drive, Newport Beach, California 92660. You may also call this toll-free telephone number to request

iii

other information about the Fund or to make shareholder inquiries. The Statement of Additional Information and the most recent annual and

semi-annual reports are available free of charge on the Fund’s website at www.pimco.com. Information on, or accessible through, the Fund’s

website is not a part of, and is not incorporated into, this prospectus. You may also access reports and other information about the Fund on the

EDGAR Database on the SEC’s Internet site at www.sec.gov. You may get copies of this information, with payment of a duplication fee, by

electronic request at the following E-mail address: publicinfo@sec.gov.

The Fund has not authorized anyone to provide you with information other than that contained or incorporated by reference in this prospectus.

The Fund does not take any responsibility for, and does not provide any assurances as to the reliability of, any other information that others may

give you. The Fund is not making an offer of these securities in any jurisdiction where the offer is not permitted. You should not assume that the

information contained in this prospectus is accurate as of any date other than the date on the front of this prospectus. The Fund’s business,

financial condition, results of operations and prospects may have changed since that date.

PIMCO California Flexible Municipal

Income Fund

Prospectus Summary

This is only a summary. This summary may not contain all of the

information that you should consider before investing in PIMCO

California Flexible Municipal Income Fund (the “Fund”) shares of

beneficial interest, par value of $0.00001 per share (the “Common

Shares”). You should review the more detailed information contained in

this prospectus and in the Statement of Additional Information. In

particular, you should carefully read the risks of investing in the Fund’s

Common Shares, as discussed under “Principal Risks of the Fund.”

The Fund

The Fund is a non-diversified, closed-end management investment

company that continuously offers its Common Shares. The Fund

commenced operations on June 27, 2022. The Fund is operated as an

“interval fund” (as defined below). The Fund currently has five separate

classes of Common Shares: Institutional Class, Class A-1, Class A-2,

Class A-3 and Class A-4.

Continuous Offering

The Fund continuously offers its Common Shares through PIMCO

Investments LLC (the “Distributor”), as principal underwriter, on a best

efforts basis. Except as set forth below, Common Shares are sold at their

offering price, which is net asset value (“NAV”) per share. While neither

the Fund nor the Distributor impose an initial sales charge on

Institutional Class, Class A-1 or Class A-3 Common Shares, if you buy

Institutional Class, Class A-1 or Class A-3 Common Shares through

certain financial firms, they may directly charge you transaction or other

fees in such amount as they may determine. Please consult your

financial firm for additional information.

Unless you are eligible for a waiver, Class A-2 and Class A-4 Common

Shares are sold at a public offering price equal to their net asset value

plus an initial sales charge. The initial sales charge varies depending

upon the size of your purchase. The minimum initial investment for

Institutional Class Common Shares is $1 million per account. The

minimum initial investment for Class A-1, Class A-2, Class A-3 and

Class A-4 Common Shares is $2,500 per account. These investment

minimums may be higher or lower for certain financial firms that submit

orders on behalf of their customers, the Trustees and certain employees

and their extended family members of Pacific Investment Management

Company LLC (“PIMCO” or the “Investment Manager”) and its

affiliates. The minimum subsequent investment amount for Class A-1,

Class A-2, Class A-3 and Class A-4 Common Shares is $50. Proceeds

from the offering will be held by the Fund’s custodian.

For additional information regarding each share class please see “Plan

of Distribution – Share Classes” in this prospectus. The Fund and the

Distributor each reserves the right, in its sole discretion, to reject any

purchase order, in whole or in part, when, in the judgment of

management, such rejection is in the best interests of the Fund.

Shareholders will not have the right to redeem their Common Shares.

However, as described below, in order to provide some liquidity to

shareholders, the Fund will conduct periodic repurchase offers for a

portion of its outstanding Common Shares.

Periodic Repurchase Offers

The Fund is an “interval fund,” a type of fund which, in order to provide

liquidity to shareholders, has adopted a fundamental investment policy

to make quarterly offers to repurchase between 5% and 25% of its

outstanding Common Shares at NAV. Subject to applicable law and

approval of the Fund’s Board of Trustees (the “Board” or “Board of

Trustees”), for each quarterly repurchase offer, the Fund currently

expects to offer to repurchase 10% of the Fund’s outstanding Common

Shares at NAV. Written notification of each quarterly repurchase offer

(the “Repurchase Offer Notice”) will be sent to shareholders at least

21 calendar days before the repurchase request deadline (i.e., the date

by which shareholders can tender their Common Shares in response to a

repurchase offer) (the ��Repurchase Request Deadline”). Subject to

Board approval, Repurchase Request Deadlines are expected to occur

each February, May, August and November, and Repurchase Offer

Notices are expected to be sent each January, April, July and October

preceding each such Repurchase Request Deadline. The Fund’s Common

Shares are not listed on any securities exchange, and the Fund does not

anticipate that a secondary market will develop for its Common Shares.

Accordingly, you may not be able to sell Common Shares when and/or

in the amount that you desire. Investors should consider Common

Shares of the Fund to be an illiquid investment. Thus, the Common

Shares are appropriate only as a long-term investment. In addition, the

Fund’s repurchase offers may subject the Fund and shareholders to

special risks. See “Principal Risks of the Fund — Repurchase Offers

Risk.”

Investment Objectives and Principal Strategies

Investment Objectives

The Fund seeks to provide high current income exempt from federal and

California income tax. Capital appreciation is a secondary objective. The

Fund attempts to achieve these objectives by investing, under normal

circumstances, at least 80% of its net assets (plus any borrowings for

investment purposes) in a portfolio of municipal bonds and other

municipal securities, the interest from which, in the opinion of bond

counsel for the issuer at the time of issuance (or on the basis of other

authority believed by PIMCO to be reliable), is exempt from federal

income tax and California income tax (i.e., excluded from gross income

for income tax purposes but not necessarily exempt from the alternative

minimum tax or from the income taxes of any other state or of a local

government), as described under “Portfolio Contents” below. In

pursuing its investment objectives, the Fund may invest without limit in

investment grade securities and may invest without limit in below

investment grade securities.

Portfolio Management Strategies

Flexible allocation strategy.

The Fund seeks to achieve its

investment objectives by utilizing a flexible, multi-sector tax-efficient

approach to investing, under normal circumstances, primarily in

municipal bonds and other municipal securities that carry interest

payments that are exempt from federal and California income tax. The

PIMCO California Flexible Municipal Income Fund |

Prospectus

principal issuers of these securities are state and local governments and

their agencies located in any of the fifty states, as well as in Puerto Rico

and other U.S. territories and possessions. To a lesser extent, the Fund

also expects to invest in a full range of preferred securities with an

emphasis on preferred securities that, at the time of issuance, are

eligible to pay dividends that qualify for certain favorable federal income

tax treatment. With PIMCO's macroeconomic analysis as the basis for

top-down investment decisions, the Fund seeks to offer investors an

actively-managed municipal bond portfolio that aims to capitalize on

what PIMCO believes are attractive opportunities in California and, to a

lesser extent, other states, and across sectors within the California and

U.S. municipal markets.

Investment selection strategies.

In selecting securities for the

Fund, PIMCO develops an outlook for interest rates and the economy,

analyzes credit and call risks, and uses other security selection

techniques. The proportion of the Fund's assets committed to

investment in securities with particular characteristics (such as quality,

sector, interest rate or maturity) varies based on PIMCO's outlook for the

U.S. economy.

PIMCO attempts to preserve and enhance the value of the Fund's

holdings relative to the municipal bond market, generally, using

proprietary analytical models that test and evaluate the sensitivity of

those holdings to changes in interest rates and yield relationships. There

is no guarantee that PIMCO's investment selection techniques will

produce the desired results.

Credit quality.

The Fund may invest without limit in municipal bonds

and other securities of any credit quality, including without limitation, in

securities that are, at the time of purchase, rated below “investment

grade” by at least one of Moody's Investors Service, Inc. (“Moody's”),

S&P Global Ratings (“S&P”) or Fitch, Inc. (“Fitch”), or unrated but

determined by PIMCO to be of comparable quality. “Investment grade”

means a rating, in the case of Moody's, of Baa3 or higher, or in the case

of S&P and Fitch, of BBB- or higher. Bonds of below investment grade

quality are regarded as having predominantly speculative characteristics

with respect to capacity to pay interest and repay principal and are

commonly referred to as “junk bonds.” Bonds in the lowest investment

grade category may also be considered to possess some speculative

characteristics by certain rating agencies. The Fund may also invest

without limit in investment grade securities. The Fund generally expects

to invest at least 60% of its total assets in above investment grade

securities and not more than 40% of its total assets in below

investment grade securities, but may determine to allocate more heavily

or exclusively to either category at any time and from time to time based

on PIMCO's economic outlook, market conditions, and other factors.

Independent credit analysis.

PIMCO relies primarily on its own

analysis of the credit quality and risks associated with individual

municipal bonds and other municipal securities considered for the Fund,

rather than relying exclusively on rating agencies or third-party research.

The Fund's portfolio managers utilize this information in an attempt to

manage credit risk and to identify investments that are undervalued or

that offer attractive yields relative to PIMCO's assessment of their credit

characteristics. This aspect of PIMCO's capabilities will be particularly

important to the extent that the Fund invests in high yield municipal

bonds or other securities.

Duration management.

The Fund does not target a specific duration

or maturity for the municipal bonds and other securities in which it

invests, and the Fund's average portfolio duration, as calculated by

PIMCO may vary significantly depending on market conditions and other

factors. There is no limit on the maturity or duration of any individual

security in which the Fund may invest. Duration is a measure used to

determine the sensitivity of a security's price to changes in interest

rates. The longer a security's duration, the more sensitive it will be to

changes in interest rates. The portfolio managers focus on municipal

bonds with the potential to offer attractive current income, typically

looking for bonds that can provide consistently attractive current yields

or that are trading at competitive market prices. Capital appreciation, if

any, generally arises from decreases in interest rates or improving credit

fundamentals for a particular state, municipality or issuer.

Portfolio Contents

The Fund will invest, under normal circumstances, at least 80% of its

net assets (plus any borrowings for investment purposes) in a portfolio

of municipal bonds and other municipal securities, the interest from

which, in the opinion of bond counsel for the issuer at the time of

issuance (or on the basis of other authority believed by PIMCO to be

reliable), is exempt from federal income tax and California income tax

(i.e., excluded from gross income for income tax purposes but not

necessarily exempt from the alternative minimum tax or from the

income taxes of any other state or of a local government) (the “80%

policy”). California municipal bonds generally are issued by or on behalf

of the State of California and its political subdivisions, financing

authorities and their agencies. By concentrating its investments in

California municipal securities, the Fund will be subject to California

State-Specific Risk, among other risks. Both within and outside the 80%

policy, the Fund may invest in debt securities of an issuer located

outside of California. The Fund's 80% policy is a fundamental policy,

which may not be changed without the approval of the holders of a

majority of the Fund's outstanding Common Shares and

Preferred

(as defined below

) voting together as a single class, and of the

holders of a majority of the outstanding Preferred Shares voting as a

separate class.

The Fund may invest without limit in municipal bonds and other

securities that are rated below investment grade (or unrated but

determined by PIMCO to be of comparable quality). Bonds of below

investment grade quality are regarded as having predominantly

speculative characteristics with respect to capacity to pay interest and

repay principal and are commonly referred to as “junk bonds.” The Fund

may also invest without limit in investment grade securities.

Included within the general category of municipal bonds in which the

Fund may invest are loans (including participations and assignments)

and participations in lease obligations. A lease obligation is an

obligation in the form of a lease or installment purchase that is issued

by a state or local government to acquire equipment and facilities.

Income from such obligations generally is exempt from state and local

April 30, 2023

(as supplemented January

12, 2024)

Prospectus

PIMCO California Flexible Municipal Income Fund

tax in the state of issuance. Lease obligations may be secured or

unsecured. Lease obligations do not constitute general obligations of

the municipality for which the municipality's taxing power is pledged.

The Fund may invest in and/or originate loans, including, without

limitation, to, on behalf of, authorized by, sponsored by, and/or in

connection with a project for which authority and responsibility lies with

one or more U.S. states or territories, cities in a U.S. state or territory, or

political subdivisions, agencies, authorities or instrumentalities of such

states, territories or cities, which may be in the form of whole loans,

assignments, participations, secured and unsecured notes, senior and

second lien loans, mezzanine loans, bridge loans or similar investments,

including to borrowers that are unrated or have credit ratings that are

determined by one or more nationally recognized statistical rating

organizations (“NRSROs”) and/or PIMCO to be below investment

grade. This may include loans to public or private firms or individuals,

such as in connection with housing development projects. The loans the

Fund invests in or originates may vary in maturity and/or duration. The

Fund is not limited in the amount, size or type of loans it may invest in

and/or originate, including with respect to a single borrower or with

respect to borrowers that are determined to be below investment grade,

other than pursuant to any applicable law. The Fund's investment in or

origination of loans may also be limited by the requirements the Fund

intends to observe under Subchapter M of the Internal Revenue Code of

1986, as amended (the “Code”), in order to qualify as a regulated

investment company (a “RIC”). The loans acquired by the Fund may be

of the type that count towards the Fund's 80% policy or they may be

loans that produce income that is subject to regular federal income tax

or California income tax.

In addition to the other types of securities and assets described in this

section, the Fund may invest the balance of its assets (i.e., not towards

its 80% policy noted above) in securities and assets that produce

taxable income. Such assets are normally expected to include, but are

not limited to, preferred securities, with an emphasis on preferred

securities that, at the time of issuance, are eligible to pay dividends that

qualify for certain favorable federal income tax treatment, such as

dividends that are treated as qualified dividend income and eligible for

the dividends received deduction (in each instance, provided certain

requirements and holding periods are satisfied). The Fund may also

invest non-80% policy assets in other municipal bonds (like those of

other jurisdictions, such as New York and Puerto Rico). See “Tax

Matters.” It is possible that the Fund could own no preferred securities

at any given time, including, for example, if municipal securities are

expected to produce a higher yield than preferred securities on an

after-tax basis.

Subject to the Fund's investment policies described above, the Fund may

invest in other securities, including commercial paper, securities eligible

for resale under Rule 144A of the Securities Act of 1933, as amended

(the “1933 Act”), and other privately placed securities, and other debt

securities subject to federal and/or California income tax, including

privately negotiated debt obligations with respect to which the principal

and/or interest is determined by reference to the performance of a

benchmark asset, market or interest rate (an “embedded index”), such

as specific securities, an index of securities or specified interest rates, or

the differential performance of two assets or markets, such as indexes

reflecting bonds. The rate of interest on an income-producing security

may be fixed, floating or variable. The Fund may also engage in credit

spread trades. A credit spread trade is an investment position relating to

a difference in the prices or interest rates of two bonds or other

securities, in which the value of the investment position is determined

by changes in the difference between the prices or interest rates, as the

case may be, of the respective securities. The Fund may purchase and

sell securities on a when-issued, delayed delivery or forward

commitment basis and may engage in short sales. The Fund may invest

in trust certificates issued in tender option bond programs. In these

programs, a trust typically issues two classes of certificates and uses the

proceeds to purchase municipal securities having relatively long

maturities and bearing interest at a fixed interest rate substantially

higher than prevailing short-term tax-exempt rates. The Fund may also

invest up to 5% of its total assets in securities of other investment

companies (including those advised by PIMCO), including closed-end

funds, exchange-traded funds and other open-end funds, that invest

primarily in municipal bonds and other municipal securities of the types

in which the Fund may invest directly.

The Fund may, but is not required to, invest in derivative instruments,

such as options, futures or forward contracts or swap agreements. For

purposes of the Fund's 80% policy, the Fund values its derivative

instruments based on their market value. The Fund may, without

limitation, seek to obtain market exposure to the securities in which it

primarily invests by entering into a series of purchase and sale contracts

or by using other investment techniques (such as buy backs or dollar

rolls).

To the extent consistent with the applicable liquidity requirements for

interval funds under Rule 23c-3 of the Investment Company Act of

1940, as amended (the “Act”), the Fund may invest without limit in

illiquid investments.

Use of

Leverage

The Fund currently

utilizes leverage through its outstanding

Remarketable Variable Rate MuniFund Term Preferred Shares (“RVMTP

Shares” and

together with any other preferred

shares the Fund may

have outstanding,

“

Preferred Shares

”)

. The Fund may also choose to

add leverage through the use of

tender option bonds, the issuance of

additional Preferred Shares or the use of

reverse repurchase

agreements, selling

credit default swaps, dollar rolls/buy backs or

borrowings, such as through bank loans or commercial paper and/or

other credit facilities. The Fund may also enter into transactions other

than those noted above that may give rise to a form of leverage

including, among others, futures and forward contracts (including

foreign currency exchange contracts), total return swaps and other

derivative transactions, loans of portfolio securities, short sales and

when-issued, delayed delivery and forward commitment transactions.

The Fund may utilize certain kinds of leverage, including, without

limitation, tender option bonds, opportunistically and may choose to

3 Prospectus

| PIMCO California Flexible Municipal Income Fund

Prospectus

increase or decrease, or eliminate entirely, its use of leverage over time

and from time to time based on PIMCO's assessment of the yield curve

environment, interest rate trends, market conditions and other factors.

The Fund may

also determine to increase its

leverage

through the

issuance of additional Preferred Shares, or decrease the leverage it

currently maintains through its

outstanding Preferred Shares

through

Preferred Share redemptions or tender

offers and may or may not

determine to replace such leverage

. The Fund may issue

additional

Preferred Shares without the approval of holders of

Common Shares

(“Common Shareholders”). If

the Fund issues

additional

Preferred

Shares in the future, all costs and expenses relating to the issuance and

ongoing maintenance of the Preferred Shares will be borne by the

Common Shareholders, and these costs and expenses may be

significant. Leveraging transactions pursued by the Fund may increase

its duration and sensitivity to interest rate movements. The

Fund’

s net

assets attributable to its Preferred Shares and the net

proceeds the Fund

obtains from the

issuance of additional Preferred Shares

or the use of

tender option bonds

or other forms of leverage will be invested in

accordance with the Fund

’

s investment objectives and policies as

described in this prospectus. So long as the rate of return, net of

applicable Fund expenses, on the debt obligations and other

investments purchased by the Fund exceeds the dividend rates payable

on the Preferred Shares together with the costs to the Fund of

other

leverage it utilizes

, the investment of the Fund

’

s assets attributable to

leverage will generate more income than will be needed to pay the costs

of the leverage. If so, and all other things being equal, the excess may be

used to pay higher dividends to Common Shareholders than if the Fund

were not so leveraged.

The Fund is subject to the requirement under the Act that an investment

company satisfy an asset coverage requirement of 300% of its

indebtedness measured at the time the investment company incurs the

indebtedness. This means that at any given time the value of the Fund's

total indebtedness may not exceed one-third the value of its total assets

(including assets attributable to such leverage). The interests of persons

with whom the Fund enters into leverage arrangements will not

necessarily be aligned with the interests of the Fund's shareholders and

such persons will have claims on the Fund's assets that are senior to

those of the Fund's shareholders.

Under the Act, the Fund is not permitted to issue Preferred Shares

unless, immediately after such issuance, the value of the Fund's total net

assets (as defined below) is at least 200% of the liquidation value of

any outstanding Preferred Shares and the newly issued Preferred Shares

plus the aggregate amount of any senior securities of the Fund

representing indebtedness (i.e., such liquidation value plus the

aggregate amount of senior securities representing indebtedness may

not exceed 50% of the Fund's total net assets). In addition,

the Fund

not

permitted to declare any cash dividend or other distribution on its

Common Shares unless, at the time of such declaration, the value of the

Fund's total net assets satisfies the above-referenced 200% coverage

requirement.

The Fund may enter into derivatives or other transactions that may

provide leverage (other than through the issuance of Preferred Shares or

bank borrowing). Rule 18f-4 under the Act (the “Derivatives Rule”)

regulates a registered investment company's use of derivatives and

certain other transactions that create future payment and/or delivery

obligations by the Fund. This new rule became operative in August

2022. The Derivatives Rule prescribes specific value-at-risk (“VaR”)

leverage limits that apply to the Fund (although the Fund in the future

could qualify as a limited derivatives user (as defined in the Derivatives

Rule) and would therefore not be subject to all of the requirements of

the Derivatives Rule). VaR is an estimate of potential losses on an

instrument or portfolio over a specified time horizon and at a given

confidence level. The Fund may apply a relative VaR test or an absolute

VaR test (if the Fund's derivatives risk manager determines that a

designated reference portfolio would not provide an appropriate

reference portfolio for purposes of the relative VaR test). The limit under

the relative VaR test when a fund has outstanding preferred shares is

250% (or 200% when no preferred shares are outstanding) of the VaR

of a designated reference portfolio, which, very generally, may be a

designated unleveraged index or the Fund's securities portfolio

excluding derivatives. If applicable, the limit under the absolute VaR test

when the Fund has outstanding preferred shares is 25% (or 20% when

no preferred shares are outstanding) of the value of a fund's net assets.

The Derivatives Rule also generally requires the Fund to appoint a

derivatives risk manager, maintain a derivatives risk management

program (“DRMP”) designed to identify, assess, and reasonably

manage the risks associated with transactions covered by the rule, and

abide by certain board and other reporting obligations and

recordkeeping requirements. With respect to reverse repurchase

agreements or other similar financing transactions in particular, the

Derivatives Rule permits a fund to enter into such transactions if the

fund either (i) complies with the asset coverage requirements of

Section 18 of the Act, and combines the aggregate amount of

indebtedness associated with all reverse repurchase agreements and

similar financing with the aggregate amount of any other senior

securities representing indebtedness when calculating the relevant asset

coverage ratio, or (ii) treats all reverse repurchase agreements and

similar financing transactions as derivatives transactions for all purposes

under the Derivatives Rule. The Fund has adopted procedures for

investing in derivatives and other transactions in compliance with the

Derivatives Rule. Compliance with the Derivatives Rule could adversely

affect the value or performance of the Fund. Limits or restrictions

applicable to the counterparties or issuers, as applicable, with which the

Fund may engage in derivative transactions could also limit or prevent

the Fund from using certain instruments.

The Fund

’s ability to utilize leverage

also

limited by asset coverage

requirements and other guidelines imposed by the terms of the

Preferred Shares and

are

imposed by rating agencies that provide

ratings for the Preferred Shares

which

are

more restrictive than the

limitations imposed by the Act noted above. Please see “Description of

Capital Structure and Shares

Preferred Shares.”

April 30, 2023

(as supplemented January

12, 2024)

Prospectus

PIMCO California Flexible Municipal Income Fund

Leveraging is a speculative technique and there are special risks and

costs involved. The Fund cannot assure you that its use of

Preferred

Shares and any other

forms of leverage (such as tender option bonds)

will be successful or result in a higher yield on your Common Shares.

When leverage is used, the net asset value of the Common Shares and

the yield to Common Shareholders will be more volatile. In addition,

dividends paid on

Preferred Shares (including

the

Preferred Shareholder

Gross-Up (as

described below)) and interest and other expenses borne

by the Fund with respect to its use of tender option bonds or other

forms of leverage are borne by the Common Shareholders (and not by

the holders of Preferred Shares

(“Preferred

Shareholders

”

)

and result in

a reduction of the net asset value of the Common Shares. In addition,

because the fees received by the Investment Manager are based on the

total managed assets of the Fund, which includes total assets of the

Fund (including assets attributable to any reverse repurchase

agreements, dollar rolls

, tender option bonds, borrowings and Preferred

Shares that may be outstanding, if any), the Investment Manager has a

financial incentive for the Fund to use certain forms of leverage (e.g.,

Preferred Shares and

tender option bonds

), which may create a conflict

of interest between the Investment Manager, on the one hand, and the

Common Shareholders, on the other hand.

Please see “Use of Leverage,” “Principal Risks of the Fund – Leverage

Risk” for additional information regarding leverage and related risks.

Investment Manager

PIMCO serves as the Investment Manager for the Fund. Subject to the

supervision of the Board, PIMCO is responsible for managing the

investment activities of the Fund and the Fund's business affairs and

other administrative matters. David Hammer, Amit Arora and Kyle

Christine are jointly and primarily responsible for the day-to-day

management of the Fund.

PIMCO is located at 650 Newport Center Drive, Newport Beach, CA

92660. Organized in 1971, PIMCO provides investment management

and advisory services to private accounts of institutional and individual

clients and to RICs. PIMCO is a majority-owned indirect subsidiary of

Allianz SE, a publicly traded European insurance and financial services

company. As of December 31, 2022, PIMCO had approximately $1.74

trillion in assets under management.

Distributions

The Fund intends to distribute substantially all of its net investment

income to shareholders in the form of dividends. The Fund intends to

declare income dividends daily and distribute them monthly to

shareholders of record.

Distributions

can only be made from net

investment income after paying any accrued dividends to holders of the

Preferred Shares. At least annually, the Fund also intends to distribute to

you your pro rata share of any available net capital gain and taxable

ordinary income, if any. Net short-term capital gains may be paid more

frequently. The dividends that the Fund pays will depend on a number of

factors, including dividends payable on any Preferred Shares issued by

the Fund, including

the

Preferred Shareholder Gross-Up (as defined and

described below) (and expenses associated with other forms of

leverage).

Although it does not currently intend to do so, the Board may change

the Fund’s dividend policy and the amount or timing of Fund

distributions, based on a number of factors. Unless shareholders specify

otherwise, dividends will be reinvested in Common Shares of the Fund

in accordance with the Fund’s dividend reinvestment plan (the “Plan”).

The Fund may pay distributions from sources that may not be available

in the future and that are unrelated to the Fund’s performance, such as

from offering proceeds and/or borrowings. See “Distributions” and

“Dividend Reinvestment Plan.”

The

Preferred Shares

pay dividend distributions at a stated

rate, which

rate

based generally on the assumption that such dividend

distributions will consist entirely of dividends that pass through the

character of exempt interest earned by the Fund and are therefore not

taxable to shareholders for regular federal and California income tax

purposes (“exempt-interest dividends”). Internal Revenue Service

(“IRS”) rules nonetheless require a RIC having two or more classes of

stock for U.S. federal income tax purposes to characterize amounts

distributed as dividends to each class for the taxable year in accordance

with their pro rata share of income or gains of any type. Therefore,

the

Fund might be required to characterize a portion of dividends paid to

Preferred Shareholders as ordinary income or capital gain dividends. The

terms of such Preferred Shares

provide further that, in the event less

than the entire amount of any particular dividend distribution paid

pursuant to the stated rate were to consist of “exempt-interest

dividends” (i.e., if a portion of any particular dividend were to derive

from ordinary income or capital gain, including short-term capital gain

taxable as ordinary income when distributed), the amount of such

dividend would increase by an amount (

the

“Preferred Shareholder

Gross-Up”) such that the after-tax amount of such dividend, as

increased by the Preferred Shareholder Gross-Up, would equal the total

amount the holder of such Preferred Shares would have received if the

dividend at the stated rate had consisted entirely of “exempt-interest

dividends.” Any Preferred Shareholder Gross-Up would reduce the

amount that would otherwise be distributable to Common

Shareholders.

The Fund might not distribute all or a portion of any net capital gain for

a taxable year. If the Fund does not distribute all of its net capital gain

for a taxable year, it will pay federal income tax on the retained gain.

Each Common Shareholder of record as of the end of the Fund's taxable

year will include in income for federal income tax purposes, as

long-term capital gain, his or her share of the retained gain, will be

deemed to have paid his or her proportionate share of the tax paid by

the Fund on such retained gain, and will be entitled to an income tax

credit or refund for that share of the tax. The Fund will treat the retained

capital gain amount as a substitute for equivalent cash distributions. The

Fund will send shareholders detailed tax information with respect to the

Fund's distributions annually. See “Tax Matters.”

5 Prospectus

| PIMCO California Flexible Municipal Income Fund

Prospectus

Distributor, Custodian and Transfer Agent

PIMCO Investments LLC, an affiliate of PIMCO, serves as the Fund’s

principal underwriter and distributor. State Street Bank and Trust

Company serves as the primary custodian of the Fund’s assets and also

provides certain fund accounting, sub-administrative and compliance

services to the Fund on behalf of the Investment Manager. UMB Bank,

n.a. serves as a custodian of the Fund for the purpose of processing

investor subscriptions and repurchases. SS&C Global Investor and

Distribution Solutions, Inc.

serves as the Fund’s transfer agent and

dividend disbursement agent.

The Bank of New

York Mellon serves as

transfer agent, registrar, redemption and paying agent and calculation

agent with respect to the RVMTP Shares.

Unlisted Closed-End Fund Structure; Limited

Liquidity

The Fund's Common Shares are not listed for trading on any securities

exchange. There is currently no secondary market for its Common Shares

and the Fund does not expect any secondary market to develop for its

Common Shares. Shareholders of the Fund are not able to have their

Common Shares redeemed or otherwise sell their Common Shares on a

daily basis because the Fund is an unlisted closed-end fund. In order to

provide liquidity to shareholders, the Fund is structured as an “interval

fund” and conducts periodic repurchase offers for a portion of its

outstanding Common Shares, as described herein. Investors should

consider Common Shares of the Fund to be an illiquid investment. An

investment in the Fund is suitable only for long-term investors who can

bear the risks associated with the limited liquidity of the Common

Shares. Investors should consider their investment goals, time horizons

and risk tolerance before investing in the Fund.

Investor Suitability

An investment in the Fund involves a considerable amount of risk. It is

possible that you will lose money. An investment in the Fund is suitable

only for investors who can bear the risks associated with the limited

liquidity of the Common Shares and should be viewed as a long-term

investment. Before making your investment decision, you should (i)

consider the suitability of this investment with respect to your

investment objectives and personal financial situation and (ii) consider

factors such as your personal net worth, income, age, risk tolerance and

liquidity needs. An investment in the Fund should not be viewed as a

complete investment program.

Principal Risks of the Fund

New/Small Fund Risk

A new or smaller fund’s performance may not represent how the Fund is

expected to or may perform in the long term if and when it becomes

larger and has fully implemented its investment strategies. Investment

positions may have a disproportionate impact (negative or positive) on

performance in a new and smaller fund, such as the Fund. New and

smaller funds may also require a period of time before they are invested

in securities that meet their investment objectives and policies and

achieve a representative portfolio composition. Fund performance may

be lower or higher during this “ramp-up” period, and may also be more

volatile, than would be the case after the fund is fully invested. Similarly,

a new or smaller fund’s investment strategy may require a longer period

of time to show returns that are representative of the strategy. New

funds have limited performance histories for investors to evaluate and

new and smaller funds may not attract sufficient assets to achieve

investment and trading efficiencies. If a new or smaller fund were to fail

to successfully implement its investment strategies or achieve its

investment objectives, performance may be negatively impacted, and

any resulting liquidation could create negative transaction costs for the

fund and tax consequences for investors.

Interest Rate Risk

Interest rate risk is the risk that fixed income securities and other

instruments in the Fund’s portfolio will fluctuate in value because of a

change in interest rates. Interest rate changes can be sudden and

unpredictable, and the Fund may lose money as a result of movements

in interest rates. The Fund may not be able to effectively hedge against

changes in interest rates or may choose not to do so for cost or other

reasons.

A wide variety of factors can cause interest rates or yields of

U.S. Treasury securities (or yields of other types of bonds) to rise

including, but not limited to, central bank monetary policies, changing

inflation or real growth rates, general economic conditions, increasing

bond issuances or reduced market demand for low yielding investments.

Risks associated with rising interest rates are heightened under current

market conditions given that the U.S. Federal Reserve (the “Federal

Reserve”) has begun to raise interest rates from historically low levels

and has signaled an intention to continue to do so. Further, in market

environments where interest rates are rising, issuers may be less willing

or able to make principal and interest payments on fixed-income

investments when due.

Fixed income securities with longer durations tend to be more sensitive

to changes in interest rates, usually making them more volatile. Duration

is a measure used to determine the sensitivity of a security’s price to

changes in interest rates that incorporates a security’s yield, coupon,

final maturity and call features, among other characteristics. Duration is

useful primarily as a measure of the sensitivity of a fixed income

security’s market price to interest rate (i.e., yield) movements. All other

things remaining equal, for each one percentage point increase in

interest rates, the value of a portfolio of fixed income investments would

generally be expected to decline by one percent for every year of the

portfolio’s average duration above zero. For example, the value of a

portfolio of fixed income securities with an average duration of eight

years would generally be expected to decline by approximately 8% if

interest rates rose by one percentage point.

During periods of very low or negative interest rates, the Fund may be

unable to maintain positive returns. Very low or negative interest rates

may magnify interest rate risk. Changing interest rates, including rates

that fall below zero, may have unpredictable effects on markets, may

April 30, 2023

(as supplemented January

12, 2024)

Prospectus

PIMCO California Flexible Municipal Income Fund

result in heightened market volatility and may detract from the Fund’s

performance to the extent the Fund is exposed to such interest rates in

connection with management of the Fund.

Municipal Bond Risk

Investing in the municipal bond market involves the risks of investing in

debt securities generally and certain other risks. The amount of public

information available about the municipal bonds in which the Fund may

invest is generally less than that for corporate equities or bonds, and the

investment performance of the Fund’s investment in municipal bonds

may therefore be more dependent on the analytical abilities of PIMCO

than its investments in taxable bonds. The secondary market for

municipal bonds also tends to be less well developed or liquid than

many other securities markets, which may adversely affect the Fund’s

ability to sell municipal bonds at attractive prices

The ability of municipal issuers to make timely payments of interest and

principal may be diminished during general economic downturns, by

litigation, legislation or political events, or by the bankruptcy of the

issuer. Laws, referenda, ordinances or regulations enacted in the future

by Congress or state legislatures or the applicable governmental entity

could extend the time for payment of principal and/or interest, or

impose other constraints on enforcement of such obligations, or on the

ability of municipal issuers to levy taxes. Issuers of municipal securities

also might seek protection under the bankruptcy laws. In the event of

bankruptcy of such an issuer, the Fund could experience delays in

collecting principal and interest and the Fund may not, in all

circumstances, be able to collect all principal and interest to which it is

entitled. To enforce its rights in the event of a default in the payment of

interest or repayment of principal, or both, the Fund may take

possession of and manage the assets securing the issuer's obligations

on such securities, which may increase the Fund's operating expenses.

Adverse economic, business, legal or political developments might affect

all or a substantial portion of the Fund's municipal bonds in the same

manner. The Fund will be particularly subject to these risks to the extent

that it focuses its investments in municipal bonds in a particular state or

geographic region.

The Fund may invest in trust certificates issued in tender option bond

programs. In these programs, a trust typically issues two classes of

certificates and uses the proceeds to purchase municipal securities

having relatively long maturities and bearing interest at a fixed interest

rate substantially higher than prevailing short-term tax-exempt rates.

There is a risk that the Fund will not be considered the owner of a

tender option bond for federal income tax purposes, and thus will not

be entitled to treat such interest as exempt from federal income tax.

Certain tender option bonds may be less liquid or may become less

liquid as a result of, among other things, a credit rating downgrade, a

payment default or a disqualification from tax-exempt status. The Fund’s

investment in the securities issued by a tender option bond trust may

involve greater risk and volatility than an investment in a fixed rate

bond, and the value of such securities may decrease significantly when

market interest rates increase. Tender option bond trusts could be

terminated due to market, credit or other events beyond the Fund’s

control, which could require the Fund to dispose of portfolio investments

at inopportune times and prices. The Fund may use a tender option

bond program as a way of achieving leverage in its portfolio, in which

case the Fund will be subject to leverage risk. The use of tender option

bonds

will impact the Fund's duration and cause the Fund to be subject

to increased duration and interest rate risk.

The Fund may invest in revenue bonds, which are typically issued to

fund a wide variety of capital projects including electric, gas, water and

sewer systems; highways, bridges and tunnels; port and airport facilities;

colleges and universities; and hospitals. Because the principal security

for a revenue bond is generally the net revenues derived from a

particular facility or group of facilities or, in some cases, from the

proceeds of a special excise or other specific revenue source, there is no

guarantee that the particular project will generate enough revenue to

pay its obligations, in which case the Fund’s performance may be

adversely affected.

The Fund may invest in taxable municipal bonds, such as Build America

Bonds. Build America Bonds are tax credit bonds created by the

American Recovery and Reinvestment Act of 2009, which authorized

state and local governments to issue Build America Bonds as taxable

bonds in 2009 and 2010, without volume limitations, to finance any

capital expenditures for which such issuers could otherwise issue

traditional tax-exempt bonds. The Fund’s investments in Build America

Bonds or similar taxable municipal bonds will result in taxable income

and the Fund may elect to pass through to Common Shareholders the

corresponding tax credits. The tax credits can generally be used to offset

federal income taxes and the alternative minimum tax, but such credits

are generally not refundable. Taxable municipal bonds involve similar

risks as tax-exempt municipal bonds, including credit and market risk.

See “Principal Risks of the Fund – Credit Risk” and “Principal Risks of

the Fund – Market Risk.”

The Fund may invest in participations in lease obligations or installment

purchase contract obligations of municipal authorities or entities.

Although a municipal lease obligation does not constitute a general

obligation of the municipality for which the municipality's taxing power

is pledged, a municipal lease obligation is ordinarily backed by the

municipality's covenant to budget for, appropriate and make the

payments due under the municipal lease obligation. However, certain

municipal lease obligations contain “non-appropriation” clauses, which

provide that the municipality has no obligation to make lease or

installment purchase payments in future years unless money is

appropriated for such purpose on a yearly basis. In the case of a

“non-appropriation” lease, the Fund's ability to recover under the lease

in the event of non-appropriation or default will be limited solely to the

repossession of the leased property, without recourse to the general

credit of the lessee, and the disposition or re-leasing of the property

might prove difficult.

Municipal securities are also subject to interest rate, credit, and liquidity

risk.

Interest Rate Risk

. The value of municipal securities, similar to

other fixed income securities, will likely drop as interest rates rise in

the general market. Conversely, when rates decline, bond prices

generally rise.

7 Prospectus

| PIMCO California Flexible Municipal Income Fund

Prospectus

Credit Risk.

The risk that a borrower may be unable to make

interest or principal payments when they are due. Funds that invest in

municipal securities rely on the ability of the issuer to service its debt.

This subjects the Fund to credit risk in that the municipal issuer may

be fiscally unstable or exposed to large liabilities that could impair its

ability to honor its obligations. Municipal issuers with significant debt

service requirements, in the near-to mid-term; unrated issuers and

those with less capital and liquidity to absorb additional expenses

may be most at risk. To the extent the Fund invests in lower quality or

high yield municipal securities, it may be more sensitive to the

adverse credit events in the municipal market. The treatment of

municipalities in bankruptcy is more uncertain, and potentially more

adverse to debt holders, than for corporate issues.

Liquidity Risk

. The risk that investors may have difficulty finding a

buyer when they seek to sell, and therefore, may be forced to sell at a

discount to the market value. Liquidity may sometimes be impaired in

the municipal market and because the Fund primarily invests in

municipal securities, it may find it difficult to purchase or sell such

securities at opportune times. Liquidity can be impaired due to

interest rate concerns, credit events, or general supply and demand

imbalances. Depending on the particular issuer and current economic

conditions, municipal securities could be deemed more volatile

investments.

In addition to general municipal market risks, different municipal sectors

may face different risks.

Revenue bonds are secured by special tax revenues or other revenue

sources. If the specified revenues do not materialize, then the bonds

may not be repaid.

Private activity bonds are yet another type of municipal security.

Municipalities use private activity bonds to finance the development of

industrial facilities for use by private enterprise. Principal and interest

payments are to be made by the private enterprise benefiting from the

development, which means that the holder of the bond is exposed to

the risk that the private issuer may default on the bond.

Moral obligation bonds are usually issued by special purpose public

entities. If the public entity defaults, repayment becomes a “moral

obligation” instead of a legal one. The lack of a legally enforceable right

to payment in the event of default poses a special risk for a holder of

the bond because it has little or no ability to seek recourse in the event

of default.

In addition, a significant restructuring of federal income tax rates, such

as the changes to federal income tax rates that occurred in 2017, or

even serious discussion on the topic in Congress could cause municipal

bond prices to fall. The demand for municipal securities is strongly

influenced by the value of tax-exempt income to investors relative to

taxable income. Lower income tax rates potentially could reduce the

advantage of owning municipal securities.

Similarly, changes to state or federal regulation tied to a specific sector,

such as the hospital sector, could have an impact on the revenue stream

for a given subset of the market.

Municipal notes are similar to general municipal debt obligations, but

they generally possess shorter terms. Municipal notes can be used to

provide interim financing and may not be repaid if anticipated revenues

are not realized.

Puerto Rico-Specific Risk

The Fund may be affected significantly by political, economic,

environmental, social, regulatory or restructuring developments affecting

the ability of Puerto Rican municipal issuers to pay interest or repay

principal. Certain issuers of Puerto Rico municipal bonds have

experienced serious financial difficulties in the past and reoccurrence of

these difficulties may impair the ability of certain Puerto Rico issuers to

pay principal or interest on their obligations. Provisions of the Puerto

Rico Constitution and Commonwealth laws, including a

federally-appointed oversight board to oversee the Commonwealth’s

financial operations, which limit the taxing and spending authority of

Puerto Rico governmental entities may impair the ability of Puerto Rico

issuers to pay principal and/or interest on their obligations. While Puerto

Rico’s economy is broad, it does have major concentrations in certain

industries, such as manufacturing and service, and may be sensitive to

economic problems affecting those industries. Future Puerto Rico

political and economic developments, constitutional amendments,

legislative measures, executive orders, administrative regulations,

litigation, debt restructuring, and voter initiatives as well as

environmental events, natural disasters, pandemics, epidemics or social

unrest could have an adverse effect on the debt obligations of Puerto

Rico issuers.

Municipal Project-Specific Risk

The Fund may be more sensitive to adverse economic, business or

political developments if it invests a substantial portion of its assets in

the bonds of specific projects (such as those relating to education,

health care, housing, transportation, and utilities), industrial

development bonds, or in general obligation bonds, particularly if there

is a large concentration from issuers in a single state. This is because the

value of municipal securities can be significantly affected by the

political, economic, legal, and legislative realities of the particular

issuer’s locality or municipal sector events. Similarly, changes to state or

federal regulation tied to a specific sector, such as the hospital sector,

could have an impact on the revenue stream for a given subset of the

market.

Municipal Project Housing-Related Risk

The Fund may invest in the bonds of projects focused on low-income,

affordable or other housing developments and businesses located in

low-income areas or invest in or originate loans that finance or are

generally related to such projects. There are significant risks associated

with the Fund’s investment in the bonds of these types of projects and

loans related to such projects. There may be federal, state and local

governmental regulatory restrictions on the operation, rental and

transfer of these projects, such as the requirement that the owners of

these affordable housing developments rent or sell certain residential

units to persons or families of low or moderate income and that the

April 30, 2023

(as supplemented January

12, 2024)

Prospectus

PIMCO California Flexible Municipal Income Fund

amount of rent that may be charged for these units may be less than

market rates. These restrictions may adversely affect economic

performance relative to properties that are not subject to these

restrictions. There are also no assurances that a project owner will be

able to achieve and maintain sufficient rental income in order to pay all

operating expenses and maintenance and repair costs of such a project

and the debt service on the related bonds or loan on a timely basis. In

the event that a project owner is unable to pay all such costs, expenses

and debt service, a default on the related bonds or loan is likely to occur.

Loans and Other Indebtedness; Loan Participations and

Assignments Risk

Loan interests may take the form of (i) direct interests acquired during a

primary distribution or other purchase of a loan, (ii) loans originated by

the Fund or (iii) assignments of, novations of or participations in all or a

portion of a loan acquired in secondary markets. In addition to credit

risk and interest rate risk, the Fund’s exposure to loan interests may be

subject to additional risks. For example, purchasers of loans and other

forms of direct indebtedness depend primarily upon the

creditworthiness of the borrower for payment of principal and interest.

Loans are subject to the risk that scheduled interest or principal

payments will not be made in a timely manner or at all, either of which

may adversely affect the value of the loan. If the Fund does not receive

scheduled interest or principal payments on such indebtedness, the

Fund’s share price and yield could be adversely affected. Loans that are

fully secured may offer the Fund more protection than an unsecured

loan in the event of non-payment of scheduled interest or principal if

the Fund is able to access and monetize the collateral. However, the

collateral underlying a loan, if any, may be unavailable or insufficient to

satisfy a borrower’s obligation. If the Fund becomes owner, whole or in

part, of any collateral after a loan is foreclosed, the Fund may incur costs

associated with owning and/or monetizing its ownership of the

collateral.

Moreover, the purchaser of an assignment typically succeeds to all the

rights and obligations under the loan agreement with the same rights

and obligations as the assigning lender. Assignments may, however, be

arranged through private negotiations between potential assignees and

potential assignors, and the rights and obligations acquired by the

purchaser of an assignment may differ from, and be more limited than,

those held by the assigning lender.

In connection with purchasing loan participations, the Fund generally

will have no right to enforce compliance by the borrower with the terms

of the loan agreement relating to the loan, nor any rights of set-off

against the borrower, and the Fund may not directly benefit from any

collateral supporting the loan in which it has purchased the loan

participation. As a result, the Fund will be subject to the credit risk of

both the borrower and the lender that is selling the participation. In the

event of the insolvency of the lender selling a participation, the Fund

may be treated as a general creditor of the lender and may not benefit

from any set-off between the lender and the borrower. Certain loan

participations may be structured in a manner designed to prevent

purchasers of participations from being subject to the credit risk of the

lender, but even under such a structure, in the event of the lender’s

insolvency, the lender’s servicing of the participation may be delayed

and the assignability of the participation impaired.

The Fund may have difficulty disposing of loans and loan participations.

Because there is no liquid market for many such investments, the Fund

anticipates that such investments could be sold only to a limited number

of institutional investors.

Economic exposure to loan interests through the use of derivative

transactions may involve greater risks than if the Fund had invested in

the loan interest directly during a primary distribution, through direct

originations or through assignments of, novations of or participations in

a loan acquired in secondary markets since, in addition to the risks

described above, certain derivative transactions may be subject to

leverage risk and greater illiquidity risk, counterparty risk, valuation risk

and other risks.

Loan Origination Risk