SCHEDULE 14A INFORMATION

                  Proxy Statement Pursuant to Section 14(a) of
                      the Securities Exchange Act of 1934
                                (Amendment no. )


Filed by the Registrant    [X]                       
Filed by a party other than the Registrant   [ ]

Check the appropriate box:                 
[ ]  Preliminary Proxy Statement           [ ]  Confidential, for Use of the   
[X]  Definitive Proxy Statement                 Commission Only (as permitted by
[ ]  Definitive Additional Materials            Rule 14a-6(e)(2))               
[ ]  Soliciting Material Pursuant to       
     Rule 14a-11(c) or Rule 14a-12       

                           WESTAMERICA, BANCORPORATION
                ------------------------------------------------
                (Name of Registrant as Specified in Its Charter)


    ------------------------------------------------------------------------
    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)


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[X]   No fee required.
[ ]   Fee computed on table below per Exchange Act Rules 14a-6(i)(4) and 0-11.


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(2)   Aggregate number of securities to which transactions applies:

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      to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is
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[ ]   Fee paid previously with preliminary materials.
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                               [GRAPHIC OMITTED]



                               1108 Fifth Avenue
                         San Rafael, California 94901



                                March 17, 1999


To Our Shareholders:

     The Annual Meeting of  Shareholders of Westamerica  Bancorporation  will be
held at 2:00 p.m. on  Wednesday,  April 21, 1999,  at the  Fairfield  Center for
Creative Arts,  1035 West Texas Street,  Fairfield,  CA, as stated in the formal
notice accompanying this letter. We hope you will plan to attend.

     At the Annual Meeting,  the  shareholders  will be asked to elect directors
and to approve the selection of independent auditors.

     Please sign and return the  enclosed  proxy as promptly as possible so that
your shares may be represented  at the Annual  Meeting.  If you attend,  you may
vote in person even though you previously returned your proxy.

     We look forward to seeing you at the Annual Meeting on Wednesday, April 21,
1999, in our new location at the Fairfield Center for Creative Arts,  Fairfield,
California.




                                        Sincerely,


                                        /s/ David L. Payne


                                        DAVID L. PAYNE
                                        Chairman of the Board, President
                                        and Chief Executive Officer





                          WESTAMERICA BANCORPORATION
                               1108 Fifth Avenue
                         San Rafael, California 94901

                                 ------------


           Notice of Annual Meeting of Shareholders--April 21, 1999


To the Shareholders of WESTAMERICA BANCORPORATION:

     The Annual Meeting of Shareholders will be held at the Fairfield Center for
Creative Arts, Fairfield, California, on Wednesday, April 21, 1999, at 2:00 p.m.
for the purpose of:

       1. Electing 13 directors;

       2. Approving the selection of independent auditors for 1999; and

       3. Transacting such other business as may properly come before the Annual
          Meeting.

     Shareholders  of record at the close of business on February 26, 1999,  are
entitled to notice of and to vote at the Annual Meeting or any  postponement  or
adjournment  thereof. You are cordially invited to attend the Annual Meeting. If
you do not expect to be present, please complete, sign and date the accompanying
proxy and mail it at once in the enclosed  envelope.  No postage is necessary if
mailed within the United States.

     Westamerica  Bancorporation's  Annual  Report  for the  fiscal  year  ended
December 31, 1998 is enclosed.  The Annual Report  contains  financial and other
information about the activities of Westamerica Bancorporation, but it is not to
be deemed a part of the proxy soliciting materials.



                                        BY ORDER OF THE BOARD OF DIRECTORS
                                        
                                        /s/ Kris Irvine

                                        Kris Irvine
                                        Assistant Corporate Secretary


Dated: March 17, 1999

- --------------------------------------------------------------------------------

                            YOUR VOTE IS IMPORTANT


  YOU ARE URGED TO COMPLETE, SIGN, DATE AND PROMPTLY RETURN YOUR PROXY SO THAT
  YOUR SHARES MAY BE VOTED IN ACCORDANCE WITH YOUR WISHES.

- --------------------------------------------------------------------------------


                               TABLE OF CONTENTS


                                                                            Page
                                                                            ----
GENERAL .....................................................................  1
ELECTION OF DIRECTORS .......................................................  2
CERTAIN INFORMATION ABOUT THE BOARD OF DIRECTORS AND CERTAIN COMMITTEES
     OF THE BOARD ...........................................................  4
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT ..............  5
EXECUTIVE COMPENSATION ......................................................  7
OTHER ARRANGEMENTS ..........................................................  9
BOARD COMPENSATION COMMITTEE REPORT ......................................... 10
TOTAL RETURN PERFORMANCE CHART .............................................. 12
APPROVAL OF AUDITORS ........................................................ 12
OTHER MATTERS ............................................................... 13

                                       i




                          WESTAMERICA BANCORPORATION
                               1108 Fifth Avenue
                         San Rafael, California 94901

                                 ------------

                                PROXY STATEMENT

                                 March 17, 1999

                                 ------------

                                    GENERAL

     This proxy  statement is furnished in connection  with the  solicitation of
proxies by the Board of Directors  (the "Board") of  Westamerica  Bancorporation
(the  "Corporation") for use at the Annual Meeting of Shareholders to be held at
2:00 p.m., Wednesday, April 21, 1999, at the Fairfield Center for Creative Arts,
Fairfield,  California, for the purposes set forth in the accompanying Notice of
Annual Meeting of Shareholders  (the "Meeting").  This proxy statement and proxy
are being mailed to shareholders on or about March 17, 1999.

     Voting   Rights  and  Vote   Required.   Shareholders   of  record  of  the
Corporation's  common stock at the close of business on February  26, 1999,  the
record date,  are entitled to vote at the Meeting.  On that date,  approximately
39,536,464  shares of the  Corporation's  common  stock  were  outstanding.  The
determination of shareholders  entitled to vote at the Meeting and the number of
votes to which  they are  entitled  was made on the  basis of the  Corporation's
records as of the record date.

     Each  share is  entitled  to one  vote,  except  that with  respect  to the
election  of  directors,  a  shareholder  may  cumulate  votes as to  candidates
nominated prior to voting if any shareholder  gives notice of intent to cumulate
votes at the Meeting prior to the voting.  If any shareholder gives such notice,
all shareholders may cumulate their votes for nominees. Under cumulative voting,
each share  carries as many votes as the number of directors to be elected,  and
the  shareholder  may cast all of such votes for a single  nominee or distribute
them in any manner among as many nominees as desired.

     In the election of directors,  the 13 nominees receiving the highest number
of votes will be elected.  Approval of the selection of the independent auditors
will require the  affirmative  vote of a majority of the shares  represented and
voting  at the  Meeting.  Abstentions  will  not  count as votes in favor of the
election of directors or any of the other proposals.

     Quorum.  A majority of the shares entitled to vote,  represented  either in
person or by a properly executed proxy, will constitute a quorum at the Meeting.
Shares  which  abstain  from voting and "broker  non-votes"  (shares as to which
brokerage  firms have not received  voting  instructions  from their clients and
therefore do not have the  authority to vote the shares at the Meeting)  will be
counted for purposes of determining a quorum only.

     Voting of Proxies.  The shares represented by all properly executed proxies
received  in  time  for the  Meeting  will  be  voted  in  accordance  with  the
shareholders'  choices  specified  therein;  provided,  however,  that  where no
choices have been  specified,  the shares will be voted to approve the selection
of KPMG LLP as independent auditors. When exercising the powers granted to proxy
holders under the caption  "ELECTION OF DIRECTORS," the shares will be voted for
the election of directors in the manner described therein.

     The Board knows of no matters to be brought  before the Meeting  other than
the election of directors  and the selection of  independent  auditors for 1999.
If, however,  any other matters of which the Board is not now aware are properly
presented  for action,  it is the  intention of the proxy  holders  named in the
enclosed  form of proxy to vote such proxy on such  matters in  accordance  with
their best business judgment.


                                        1



     Revocability of Proxy. The delivery of the enclosed proxy does not preclude
the shareholder delivering the proxy from voting in person or changing the proxy
should  the  shareholder  so  desire.  The  proxy  may be  revoked  by a written
directive  to the  Corporation,  by  another  proxy  subsequently  executed  and
presented at the Meeting at any time prior to the actual voting or by attendance
and voting at the Meeting.

     Shareholder Proposals.  To be considered for inclusion in the Corporation's
proxy  statement for next year's annual meeting,  shareholder  proposals must be
received  at the  Corporation's  executive  offices  at 1108 Fifth  Avenue,  San
Rafael, California 94901, no later than November 18, 1999.


                              ELECTION OF DIRECTORS

     The number of  directors  of the Board to be elected at the Meeting to hold
office for the ensuing year and until their successors are elected and qualified
is 13. It is the intention of the proxy  holders named in the enclosed  proxy to
vote such proxied (except those  containing  contrary  instructions)  for the 13
nominees  named below.  The Board does not  anticipate  that any of the nominees
will be unable to serve as a  director,  but if that  should  occur  before  the
Meeting,  the proxy holders  reserve the right to substitute  another  person as
nominee and vote for such  person of their  choice in the place and stead of any
nominee  unable so to serve.  The proxy  holders  reserve  the right to cumulate
votes for the  election of  directors  and cast all of such votes for any one or
more of the  nominees,  to the  exclusion  of the  others,  and in such order of
preference as the proxy holders may determine in their discretion.

     Nominees.  The nominees for election to the office of director of the Board
are named and  certain  information  with  respect to them is given  below.  The
information  has been furnished to the  Corporation by the respective  nominees.
All of the nominees have engaged in their  indicated  principal  occupation  for
more than five years, unless otherwise indicated.


                                                                                                Director
Name of Nominee                                   Principal Occupation                           Since
- ---------------------------   ---------------------------------------------------------------   ----------
                                                                                            
Etta Allen ................     Mrs. Allen, born in 1929, is President and owner of Allen         1988
                                Heating and Sheet Metal of Greenbrae, California, and
                                President and owner of Sunny Slope Vineyard, Glen Ellen,
                                California.

Louis E. Bartolini ........     Mr. Bartolini, born in 1932, retired in 1988 as a Vice            1991
                                President and financial consultant with Merrill Lynch, Pierce,
                                Fenner & Smith, Inc. He currently devotes some of his time
                                to serving on various community service boards.

Don Emerson ...............     Mr. Emerson, born in 1928, was President of Calso Company         1979
                                (the holding company that owns the formula and name
                                "Calso Water," a carbonated mineral water) through 1981.
                                He presently devotes his time to personal investments.

Louis H. Herwaldt .........     Mr. Herwaldt, born in 1932, is Chief Executive Officer of         1997
                                Herwaldt Automotive Group, Inc. Prior to 1996, Mr.
                                Herwaldt had been President of Herwaldt Oldsmobile-GMC
                                Truck since 1969, President of Saturn of Fresno since 1991,
                                and President of Herwaldt Motors since 1993. Mr. Herwaldt
                                served as a director of ValliCorp Holdings, Inc., which
                                merged with and into the Corporation in 1997.


                                       2







                                                                                                   Director
Name of Nominee                                      Principal Occupation                           Since
- -----------------------------   ----------------------------------------------------------------   ----------
                                                                                               
Arthur C. Latno, Jr. ........    Mr. Latno, born in 1929, was an Executive Vice President for        1985
                                 Pacific Telesis Group (formerly Pacific Telephone Co.) in San
                                 Francisco, California. Mr. Latno retired from that company
                                 in November of 1992. He currently devotes some of his time
                                 to serving on various community service boards.

Patrick D. Lynch ............    Mr. Lynch, born in 1933, currently serves as a consultant to        1986
                                 several private high technology firms.

Catherine Cope                   Ms. MacMillan, born in 1947, is President and owner of The          1985
 MacMillan ..................    Firehouse Restaurant in Sacramento, California.

Patrick J. Mon Pere .........    Mr. Mon Pere, born in 1931, is the owner and President/Chief        1997
                                 Executive Officer of Patrick James Inc., a men's retail clothing
                                 firm. Mr. Mon Pere served as a director of ValliCorp Holdings,
                                 Inc., which merged with and into the Corporation in 1997.

Ronald A. Nelson ............    Mr. Nelson, born in 1942, was Vice President of Charles M.          1988
                                 Schulz Creative Associates, a general partner in various
                                 Schulz partnerships and trustee for various Schulz trusts and
                                 the Schulz foundation through 1995. He now devotes his time
                                 to personal investments.

Carl R. Otto ................    Mr. Otto, born in 1946, is the President and Chief Executive        1992
                                 Officer of John F. Otto, Inc., a general contracting firm in
                                 Sacramento, California.

David L. Payne ..............    Mr. Payne, born in 1955, is the Chairman of the Board, President    1984
                                 and Chief Executive Officer of the Corporation. Mr.
                                 Payne is President and Chief Executive Officer of Gibson
                                 Printing and Publishing Company and Gibson Radio and
                                 Publishing Company, which are newspaper, commercial
                                 printing and real estate investment companies headquartered
                                 in Vallejo, California.

Michael J. Ryan, Jr. ........    Mr. Ryan, born in 1930, has been involved in Ryan Farms, a          1997
                                 diversified farming venture, as well as investments and real
                                 estate since 1957. Mr. Ryan served as a director of ValliCorp
                                 Holdings, Inc., which merged with and into the
                                 Corporation in 1997.

Edward B. Sylvester .........    Mr. Sylvester, born in 1936, is the President of Sylvester          1979
                                 Engineering, Inc., a civil engineering and planning firm with
                                 offices in Nevada City and Truckee, California.



                                       3


                CERTAIN INFORMATION ABOUT THE BOARD OF DIRECTORS
                       AND CERTAIN COMMITTEES OF THE BOARD


     The Board held a total of 13 meetings during 1998. Every director  attended
at least 75% of the  aggregate  of: (i) the 13 Board  meetings or that number of
Board  meetings held during the period in which they served;  and (ii) the total
number of meetings of any Committee of the Board on which such director served.

     Committees of the Board. The Board has an Executive Committee,  the members
of which are D. L. Payne,  Chairman,  D. Emerson,  A. C. Latno, Jr., P. D. Lynch
and E. B. Sylvester. The Board delegates to the Executive Committee,  subject to
the  limitations  of the  California  General  Corporation  Law,  any powers and
authority  of the Board in the  management  of the  business  and affairs of the
Corporation. The Executive Committee held 12 meetings in 1998.

     The Board has an Audit  Committee,  the members of which are R. A.  Nelson,
Chairman, L. E. Bartolini,  C. C. MacMillan,  P. J. Mon Pere and C. R. Otto. The
Audit  Committee  reviews  with  the  Corporation's   independent  auditors  and
management the Corporation's  accounting principles,  policies and practices and
its  reporting  policies and  practices.  The Audit  Committee  reviews with the
independent auditors the plan and results of the auditing engagement and reviews
the scope and results of the  procedures  of the  Corporation's  Internal  Audit
Department.  The Audit Committee conducts  investigations of the adequacy of the
Corporation's  internal  accounting  procedures  and reviews the results of such
investigations  with the Corporation's  internal audit staff and with the Board.
The Audit  Committee  reviews  the  reports of  examinations  conducted  by bank
regulatory authorities. The Audit Committee held five meetings in 1998.

     The  Board has an Employee Benefits and Compensation Committee, the members
of  which  are  P. D. Lynch, Chairman, E. Allen, D. Emerson, R. A. Nelson and M.
J.  Ryan,  Jr.  The Employee Benefits and Compensation Committee administers and
carries  out  the terms of the Corporation's employee stock option plans as well
as  the  tax  deferred  savings  and  retirement  and  profit-sharing plans. The
Employee  Benefits  and  Compensation  Committee  administers  the Corporation's
compensation  programs  and reviews and recommends to the Board the compensation
level  for  the  executive officers of the Corporation and its subsidiaries. The
Employee  Benefits  and  Compensation  Committee also reviews the performance of
and  recommends  promotions  for  the executive officers of the Corporation. The
Employee Benefits and Compensation Committee held five meetings in 1998.

     The Board has a Nominating  Committee  for the election of  directors,  the
members of which are D. L. Payne,  Chairman, D. Emerson, A. C. Latno, Jr., P. D.
Lynch and E. B. Sylvester. The Nominating Committee is responsible for reviewing
the fees paid to directors for  attendance  at Board and Committee  meetings and
making  recommendations  with respect  thereto.  The  Nominating  Committee will
consider  shareholder  nominations  for  election  to  the  Board  submitted  in
accordance with section 2.14 of the Bylaws of the Corporation  ("Section 2.14").
Section 2.14 requires that  nominations be submitted in writing to the Secretary
(or  Assistant  Secretary) of the  Corporation  within not less than 14 days nor
more than 50 days prior to any  meeting at which  directors  will be elected and
that nominations contain certain specified information regarding the nominee and
the nominating shareholder. Nominations not made in accordance with Section 2.14
may  be  disregarded  by  the  chairperson  of the  Meeting  in his or her  sole
discretion. The Nominating Committee held one meeting in 1998.

     The Board has a Loan and Investment Committee,  the members of which are E.
B. Sylvester,  Chairman,  E. Allen, L. H. Herwaldt,  A. C. Latno,  Jr. and C. C.
MacMillan.  The Loan and Investment Committee is responsible for reviewing major
loans and investment  policies and for monitoring the activities  related to the
Community  Reinvestment Act. The Loan and Investment  Committee held 12 meetings
in 1998.

     Directors'  Fees.  During 1998,  directors of the  Corporation  received an
annual  retainer of $14,000.  Each director  received $1,000 for each meeting of
the Board that he or she attended.


                                        4



     During 1998,  each  nonemployee  director  received $500 for each Committee
meeting of the Board  attended.  The  Chairman  of each  Committee  received  an
additional $250, for a total of $750, for each Committee meeting  attended.  The
Chairman of the Board,  D. L. Payne,  is  compensated as an employee and did not
receive an annual retainer or directors' fees.

     Indebtedness  of  Directors  and  Management.  Certain  of  the  directors,
executive  officers  and their  associates  have had banking  transactions  with
subsidiaries  of the  Corporation  in  the  ordinary  course  of  business.  All
outstanding  loans and commitments  included in such  transactions  were made on
substantially the same terms, including interest rates and collateral,  as those
prevailing at the time for comparable  transactions with other persons,  did not
involve  more than a normal risk of  collectibility  and did not  present  other
unfavorable features.

                         SECURITY OWNERSHIP OF CERTAIN
                       BENEFICIAL OWNERS AND MANAGEMENT

     Security  Ownership of Certain  Beneficial Owners. To the best knowledge of
the Corporation, as of the date of this proxy statement, no person or entity was
the beneficial owner of more than 5% of the  Corporation's  outstanding  shares.
For the purpose of this  disclosure and the disclosure of ownership of shares by
management  below,  shares  are  considered  to be  "beneficially"  owned if the
person,  directly or  indirectly,  has or shares the power to vote or direct the
voting of the shares,  the power to dispose of or direct the  disposition of the
shares, or the right to acquire  beneficial  ownership (as so defined) within 60
days of February 26, 1999.


     Security  Ownership of Directors and Management.  The following table shows
the number of common shares and the percentage of the common shares beneficially
owned  (as  defined  above)  by each of the  current  directors,  by each of the
nominees for election to the office of director,  by the Chief Executive Officer
and the four other most highly compensated executive officers during 1998 and by
all  directors  and  executive  officers  of the  Corporation  as a group  as of
February 26, 1999.


                                            Amount and Nature of Beneficial Ownership
                                ---------------------------------------------------------------
                                   Sole        Shared Voting        Right to
                                Voting and          and          Acquire Within                     % of
                                Investment      Investment         60 Days of                     Shares of
             Name                 Power            Power         Feb 26,1999(1)       Total        Class(2)
- ------------------------------- ------------   ---------------   ----------------   -----------   -----------
                                                                                       
Etta Allen(3) .................      10,677                                             10,677         *
Louis E. Bartolini ............       1,800                                              1,800         *
Don Emerson ...................      67,650                                             67,650         *
Louis H. Herwaldt .............      30,000                                             30,000         *
Arthur C. Latno, Jr.(4) .......       3,166                                              3,166         *
Patrick D. Lynch ..............       1,200                                              1,200         *
Catherine Cope MacMillan(5) ...       1,800                                              1,800         *
Patrick J. Mon Pere ...........     220,829                            9,909           230,738         .1%
Ronald A. Nelson ..............      40,000                                             40,000         *
Carl R. Otto ..................       6,000                                              6,000         *
David L. Payne(6) .............     607,095        11,075            400,630         1,018,800        2.6%
Michael J. Ryan, Jr.(7) .......      56,885                            9,387            66,272         *
Edward B. Sylvester ...........      81,690                                             81,690         *
Jennifer J. Finger ............          76           286              4,290             4,652         *
Robert W. Entwisle(8) .........       7,335            26            123,340           130,701         *
Hans T. Y. Tjian(9) ...........      89,261        16,221            119,520           225,327         .1%
Charles L. Fritz ..............           0             0             49,950            49,950         *
All 21 Directors and Executive
 Officers as a Group ..........   1,301,938        43,886            864,515         2,210,339        5.5%

                                                  (Footnotes on following page.)

                                        5

<FN>
- ------------
*    Indicates that the percentage of the outstanding shares  beneficially owned
     is less than one percent (1%).

(1)  During  1996,  the  Corporation  adopted  the  Westamerica   Bancorporation
     Deferral Plan which allows recipients of restricted  performance  shares to
     defer income into succeeding years. Includes restricted  performance shares
     vested as of March 31, 1999,  whether or not deferred by the executive into
     the Westamerica Bancorporation Deferral Plan.

(2)  In calculating the percentage of ownership, all shares which the identified
     person or  persons  have the right to acquire by  exercise  of options  are
     deemed to be outstanding for the purpose of computing the percentage of the
     class owned by such person,  but are not deemed to be  outstanding  for the
     purpose of computing the percentage of the class owned by any other person.

(3)  Includes 10,350 shares held in a trust as to which Mrs. Allen is trustee.

(4)  Includes  1,200 shares  owned by Mr.  Latno's  wife,  as to which Mr. Latno
     disclaims beneficial ownership.

(5)  Includes 900 shares held in a trust as to which Ms. MacMillan is trustee.

(6)  Includes  528,837 shares owned by Gibson Radio and Publishing  Company,  of
     which Mr. Payne is President and Chief Executive  Officer,  as to which Mr.
     Payne disclaims beneficial ownership.

(7)  Held in a trust,  as to which Mr. Ryan is  co-trustee  with sole voting and
     investment power.

(8)  Includes  5,805  shares  held  in a  trust  as to  which  Mr.  Entwisle  is
     co-trustee with sole voting and investment power.

(9)  Held in a trust,  as to which Mr. Tjian is co-trustee  with sole voting and
     investment power.
</FN>



             Section 16(a) Beneficial Ownership Reporting Compliance

     Section  16(a) of the  Securities  Exchange  Act of 1934,  as amended  (the
"Exchange Act") requires the Corporation's  directors and executive officers and
persons who own 10% or more of a registered  class of the  Corporation's  equity
securities to file with the Securities and Exchange  Commission  (the "SEC") and
the National  Association of Securities Dealers initial reports of ownership and
reports of changes in ownership of Common Stock and other equity  securities  of
the  Corporation.  Such  persons are required by SEC  regulation  to furnish the
Corporation with copies of all Section 16(a) forms they file.

     To the Corporation's  knowledge,  based solely on a review of the copies of
such reports  furnished to the Corporation and written  representations  that no
other reports were required, during the fiscal year ended December 31, 1998, all
Section 16(a) filing requirements applicable to its officers,  directors and 10%
shareholders were complied with, except with respect to Patrick J. Mon Pere.

     During 1998, Mr. Mon Pere inadvertently failed to timely file a report on a
Form 4 concerning a purchase for Patrick James,  Inc.  employee  retirement plan
effective  October 28, 1998. This  transaction was reported on a Form 4 filed in
February 1999.


                                        6


                            EXECUTIVE COMPENSATION

     The following Summary Compensation Table sets forth the compensation of the
Corporation's Chief Executive Officer and the four other most highly compensated
executive   officers  for  services  in  all  capacities  to  the   Corporation,
Westamerica Bank ("WAB") and other subsidiaries during 1998, 1997 and 1996:



                           SUMMARY COMPENSATION TABLE


                                      Annual Compensation                   Long-Term Compensation
                         ---------------------------------------------   -----------------------------
        Name and                                                          Restricted      Securities
       Principal                                                            Stock         Underlying         All Other
        Position         Year      Salary      Bonus(1)     Other(2)     Awards(3)(4)     Options(3)      Compensation(5)
- ------------------------ ------   ----------   ----------   ----------   --------------   ------------   -----------------
                                                                                      
David L. Payne,          1998     $272,016     $300,000       $ 1,089      $       0        192,090        $   32,391(6)
Chairman,                1997      272,016      300,000         1,200              0         96,000            32,743(6)
President & CEO          1996      272,016      260,000             0              0         94,650            32,880(6)

Jennifer J. Finger(7),   1998     $129,988     $ 86,600       $     0      $       0              0        $   27,816(8)
SVP & CFO                1997       42,915       28,800             0              0              0             3,473(8)

Robert W. Entwisle,      1998     $134,280     $ 75,500       $13,089      $ 135,979         23,220        $   18,511
SVP                      1997      134,280       72,300        13,096        120,698         25,800            18,354
                         1996      134,280       66,200        12,000        127,531         25,500            17,385

Hans T. Y. Tjian,        1998     $130,008     $ 74,200       $12,000      $ 121,666         20,910        $   20,255
SVP                      1997      130,008       75,600        12,000        108,570         23,250            19,850
                         1996      130,008       68,200        12,000        113,619         22,950            18,237

Charles L. Fritz(9),     1998     $120,960     $ 66,600       $12,000      $ 121,666         20,910        $   20,749
EVP & CCO                1997      120,960       66,700        12,000        108,570         23,250            20,522
                         1996      120,960       60,200        12,000        113,619         22,950            18,905
<FN>

- ------------

(1)  Includes bonuses in the year in which they were earned.

(2)  Includes  monthly auto allowance for each  individual and the amount of any
     taxable perquisites.

(3)  The Corporation  grants restricted  performance shares and stock options in
     the first quarter of each year based on corporate  performance in the prior
     calendar year. As with all  outstanding  shares of common stock,  dividends
     are paid on vested  restricted  performance  shares.  At December  31, 1998
     these individuals held the following unvested restricted performance shares
     with the  following  fair  market  values,  based on a price of $36.75  per
     share:  Finger (1,470 shares valued at $48,201);  Entwisle  (18,510  shares
     valued at  $680,243);  Tjian  (16,560  shares valued at $608,580) and Fritz
     (16,560  shares  valued at $608,580).  The  following  table sets forth the
     restricted  performance share grants which were made on the following dates
     to the named individuals:

                                 Jan. 24, 1996    Jan. 22, 1997    Jan. 21, 1998
                                 Market Price:    Market Price:    Market Price:
                                  $15.46/Share     $19.25/Share     $32.79/Share
                                 ---------------  ---------------  -------------
       David L. Payne .........           0                0                0
       Jennifer J. Finger .....           0                0            1,470
       Robert W. Entwisle .....       8,250            6,270            3,990
       Hans T. Y. Tjian .......       7,350            5,640            3,570
       Charles L. Fritz .......       7,350            5,640            3,570

     Mr. Payne's 1995, 1996 and 1997 restricted performance shares were canceled
     by the Employee  Benefits and  Compensation  Committee on October 22, 1997,
     with Mr. Payne's consent,  in exchange for Mr. Payne receiving the right to
     receive a nonqualified  pension from the  Corporation at age 55. See "Other
     Arrangements Pension Agreement."

                                        7


(4)  Restricted  performance share grants based on corporate performance in 1998
     were made on January 26, 1999 (on which date the market  price was $34.5625
     per share) to the named  individuals as follows:  Payne--0;  Finger--3,870;
     Entwisle--3,480; Tjian--3,140; and Fritz--3,140.

(5)  Includes 1998 matching  contributions made by the Corporation under the Tax
     Deferred  Savings/Retirement  Plan  ("ESOP")  for the  accounts  of Messrs.
     Payne,  Entwisle,  Tjian  and  Fritz  and  Ms.  Finger  in the  amount  of:
     Payne--$0;    Finger--$9,553;    Entwisle--$9,600;    Tjian--$9,564;    and
     Fritz--$9,600;  and includes  1998  contributions  made by the  Corporation
     under the profit Sharing/Retirement Plan for the accounts of Messrs. Payne,
     Entwisle,   Tjian   and   Fritz,   and  Ms.   Finger   of:   Payne--$7,200;
     Finger--$7,165;  Entwisle--$7,200;  Tjian--$7,200;  and Fritz--$7,200;  and
     includes 1998 insurance  premiums paid by the  Corporation for the accounts
     of Messrs. Payne,  Entwisle,  Tjian and Fritz and Ms. Finger in the amounts
     of:  Payne--$1,008;  Finger--$428;  Entwisle--$1,711;   Tjian--$3,491;  and
     Fritz--$3,949.

(6)  Includes the dollar  value of the benefit to Mr. Payne of the  remainder of
     the premium payable by the Corporation  with respect to a split dollar life
     insurance  policy for Mr. Payne  (projected  on an actuarial  basis) in the
     amounts  of  $23,140,   $21,987  and  $21,411  for  1996,  1997  and  1998,
     respectively;  and bonus paid to Mr. Payne which he used to pay his portion
     of split dollar life  insurance  premiums in the amounts of $2,357,  $2,548
     and $2,772 for 1996, 1997 and 1998, respectively.

(7)  Ms. Finger began her employment in September 1997. 

(8)  Includes  relocation expenses  of  $10,670  in 1998 and $3,330 in 1997.

(9)  Mr. Fritz retired effective December 31, 1998, but pursuant to an agreement
     will continue to receive compensation through approximately April 1, 1999.
</FN>


     The following table  describes stock options that were granted  pursuant to
the  Westamerica  Bancorporation  1995 Stock Option Plan (the "1995 Stock Option
Plan") to the  Corporation's  Chief  Executive  Officer  and the four other most
highly  compensated  executive  officers in the fiscal year ended  December  31,
1998. All of these grants were made on January 21, 1998, based on achievement of
1997 corporate performance objectives.



                       OPTION GRANTS IN LAST FISCAL YEAR


                          Number             Percent
                       of Securities         of Total                                         Grant
                        Underlying        Options Granted                                      Date
                          Options        to All Employees      Exercise      Expiration      Present
         Name           Granted(1)        in Fiscal Year        Price           Date         Value(2)
- ---------------------- ---------------   ------------------   ------------   ------------   ------------
                                                                              
David L. Payne .......    192,090                32%           $ 32.79167     1/21/2008      $1,608,370
Jennifer J. Finger ...     12,870                 2              32.79167     1/21/2008         107,760
Robert W. Entwisle ...     23,220                 4              32.79167     1/21/2008         194,421
Hans T. Y. Tjian .....     20,910                 3              32.79167     1/21/2008         175,079
Charles L. Fritz .....     20,910                 3              32.79167     1/21/2008         175,079
<FN>

- ------------

(1)  All  options are  nonqualified  stock  options  which vest  ratably  over a
     three-year  period  commencing  one year after the grant date.  All options
     have an exercise price equal to the market value on the date of grant.  The
     terms of all of the  Corporation's  stock option plans provide that options
     may  become  exercisable  in full in the  event of a change of  control  as
     defined in each stock option plan.

(2)  A Modified Roll option pricing model using standard assumptions,  including
     14.0% annual dividend  growth,  a risk-free rate equal to the six-year U.S.
     Treasury yield of 5.43%,  volatility of 20.00% and a six-year  maturity was
     used to derive the per share option value of $8.37.
</FN>


                                        8


     The following table sets forth the stock options  exercised in 1998 and the
December 31, 1998  unexercised  value of both vested and unvested  stock options
for the  Corporation's  Chief  Executive  Officer and the four other most highly
compensated executive officers.



                                      AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR
                                            AND DECEMBER 31, 1998 OPTION VALUES



                                                              Number of Securities
                                                             Underlying Unexercised             Value of Unexercised
                                                                   Options at                   In-The-Money Options
                                                                December 31, 1998              at December 31, 1998(1)
                              Shares                     -------------------------------   -----------------------------
                             Acquired        Value
           Name             on Exercise     Realized     Exercisable     Unexercisable     Exercisable      Unexercisable
- --------------------------- -------------   ----------   -------------   ---------------   -------------   ---------------
                                                                                         
David L. Payne ............  43,450         $714,066       273,050          287,640        $10,034,588      $10,570,770
Jennifer J. Finger ........     --               --            --            12,870                --           472,973
Robert W. Entwisle ........     --               --        102,850           48,920          3,779,738        1,785,580
Hans T. Y. Tjian ..........     --               --        104,800           44,060          3,851,400        1,619,205
Charles L. Fritz ..........     --               --         81,400           44,060          2,991,450        1,619,205

- ------------
<FN>

(1)  Based on the closing price of the Corporation's Common Stock of $36.75 per share on December 31, 1998.

</FN>



                               OTHER ARRANGEMENTS


Certain Employment Contracts

     WAB entered into an employment  agreement with Mr. Entwisle,  dated January
7, 1987, with an annual base salary of $134,280. The agreement is "evergreen" in
the sense  that the term of the  agreement  is  automatically  extended  for one
additional month upon completion of each additional  month of employment  unless
WAB gives Mr. Entwisle one year's notice of intent to terminate.

     WAB may terminate Mr. Entwisle's  employment without cause and Mr. Entwisle
may terminate his employment  for "good  reason," as defined in the  agreements.
Under such circumstances,  however,  Mr. Entwisle would be entitled to severance
pay  equal  to the sum of:  (i) one  time his  base  salary;  (ii)  his  maximum
bonus(es)  had he  remained  employed  one  additional  year  past  the  date of
termination;  and (iii) an amount equal to his automobile  allowance for the one
year preceding the date of termination. The agreement with Mr. Entwisle provides
for the payment of  liquidated  damages upon  termination  of  employment by WAB
without cause or termination by Mr.  Entwisle for "good reason." Under the terms
of the agreement,  the amount of liquidated  damages is reduced by any severance
pay received by Mr. Entwisle and he is under a duty to mitigate his damages.

     Hans T. Y. Tjian  accepted a position with WAB as Senior Vice President and
Manager of Operations and Systems  Administration under the terms set forth in a
letter  agreement dated April 14, 1989.  Under the terms of this agreement,  Mr.
Tjian is entitled to: (i) receive an annual  salary of $130,008;  (ii) receive a
car allowance of $1,000 per month;  (iii)  participate in WAB's  executive bonus
plan; (iv) participate in the Corporation's  Stock Option Plan; and (v) vacation
leave. In addition,  Mr. Tjian is entitled to receive severance pay equal to his
annual base salary for one year if his position is  eliminated  as a result of a
change of control.


Pension Agreement

     During 1997, the Corporation entered into a nonqualified  pension agreement
("Pension  Agreement") with Mr. Payne in consideration of Mr. Payne's  agreement
that  restricted  performance  shares  granted  in 1995,  1996 and 1997 would be
canceled.  The pension is calculated  as a percentage of Mr.  Payne's three year
average  compensation  (salary and bonus) preceding the earlier of retirement or
age  55.  The  percentage  will  be  determined  by the  Employee  Benefits  and
Compensation  Committee  (the  "Committee")  in 2000 based on the  Corporation's
achievement of certain performance goals as follows:


                                        9


   *  In 1998 the Committee  determined  that the  Corporation  had achieved the
      performance goals established for Mr. Payne's 1995 restricted  performance
      shares that were  canceled.  Under the terms of the Pension  Agreement the
      annual  pension  will  be no less  than  $190,572.  In  January  1999  the
      Committee  determined  that the  Corporation  had achieved the performance
      goals established for Mr. Payne's 1996 restricted  performance shares that
      were canceled.  Thus, under the terms of the Pension Agreement Mr. Payne's
      annual  pension will be increased by no less than an  additional  $163,503
      resulting in an annual pension of no less than $354,075.

   *  If the Committee  determines in 2000 that the Corporation has achieved the
      performance goals established for Mr. Payne's 1997 restricted  performance
      shares that were canceled, the annual pension will be increased by no less
      than an additional $157,870 per year.

     Mr. Payne's  pension will vest ratably based on his  continuous  employment
through  December  31,  2002,  with  accelerated  vesting in the event of death,
disability,  termination without cause or termination as a result of a Change of
Control (as defined in the 1995 Stock Option  Plan).  Mr. Payne will forfeit any
unvested  portion of his pension  upon  termination  of  employment.  The vested
portion of the pension  will be paid to Mr. Payne as a 20-year  certain  pension
commencing  at age 55. The minimum  amounts  set forth in the section  above for
1999 and 2000 are  indeterminate  at this time,  but the actual amounts could be
higher than the minimums set forth.

     As part of the pension agreement, if Mr. Payne becomes subject to an excise
tax as a result of the  accelerated  vesting of the pension in connection with a
Change of Control,  Mr. Payne will also receive a cash payment  equal to the sum
of (i) the portion of any excise tax due  attributable  to the vested pension in
excess  of the  portion  of any  excise  tax that  would  be due if Mr.  Payne's
restricted  performance  shares  had not been  canceled,  and  (ii)  the  amount
necessary  to restore  Mr.  Payne to the same  after-tax  position as if no such
excise tax had been imposed.


                       BOARD COMPENSATION COMMITTEE REPORT

     The  Board,  operating  through  its  Employee  Benefits  and  Compensation
Committee,  has  established  an executive  compensation  program and determines
annual  compensation  for  executives  based  on  performance.   This  executive
compensation  program and annual  evaluation  process  establishes a competitive
base  salary for each  executive  and offers  incentive  compensation  which can
provide  additional   compensation  if  established   performance  measures  are
achieved.  This additional  compensation can be in the form of short-term annual
cash  bonuses,  long-term  stock options and  long-term  restricted  performance
shares.

     As described in the Summary  Compensation Table above, each named executive
officer  receives a monthly  base  salary,  and is eligible to receive an annual
cash bonus,  an annual grant of stock  options and an annual grant of restricted
performance  shares.  Corporate  performance  measures are established each year
based on the Corporation's objectives.  The extent to which these objectives are
achieved determines if the annual option grants and restricted performance share
grants will be made and the amount of such grants.  Achievement  of these annual
performance  measures  also  determines  between  55% and 80% of the annual cash
bonus  to be  paid to each  named  executive,  with  the  remaining  45% and 20%
determined by individual and division performance.

     Corporate performance measures for 1998, which determined January 1999 cash
bonuses, option grants and restricted performance share grants, were to:

     * reach  target  levels of return on equity,  return on assets and earnings
       per share;

     * maintain credit quality measures at established levels;

     * hold   noninterest   expenses   below  a  specified  level  and  maintain
       satisfactory audit results; and

     * improve  assets  per  employee  and  revenues  per  employee to specified
       levels.

     Corporate performance measures for 1997, which determined January 1998 cash
bonuses, and option grants, were to:

     * reach  target  levels of return on equity,  return on assets and earnings
       per share;

                                       10


     * complete the acquisition of ValliCorp Holdings,  Inc. and Valliwide Bank,
       and assimilate their employees and operations into WAB;

     * maintain credit quality measures at established levels;

     * hold   noninterest   expenses  below  a  specified   level  and  maintain
       satisfactory audit results; and

     * improve  assets per  employee  and  revenues  per  employee to  specified
       levels.

     Additional  corporate  performance  objectives for a three-year  period are
established  by the Employee  Benefits and  Compensation  Committee to accompany
each grant of  restricted  performance  shares.  Whether  each grant vests three
years  following  the  date of  grant  is  determined  by  achievement  of these
preestablished, three-year performance objectives.

     The  Chief  Executive  Officer's  base  salary  in  1998  of  $272,016  was
established at a level judged to be  competitive  with  comparable  positions at
other  financial  institutions.  The Chief  Executive  Officer's  $300,000 bonus
earned in 1998  (included in the Summary  Compensation  Table  listed  above) of
which  $150,000  was paid in January of 1999 and  $150,000 to be paid in June of
1999,  was related 80% to the  achievement  of the 1998  corporate  goals listed
above and 20% to the  achievement  of  individual  management  goals.  The Chief
Executive Officer's receipt,  pursuant to the 1995 Stock Option Plan, of 192,090
nonqualified  stock  options in January 1999 was related to  achievement  of the
1998 performance measures listed above.  Individual management goals achieved in
1998 included  satisfactory results from regulatory  examinations,  satisfactory
internal  controls and satisfactory  progress on  acquisitions.  Compared to the
1998 corporate objectives listed above, the Corporation:

     * exceeded its profitability objectives;

     * improved credit quality measures to better than established levels;

     * outperformed noninterest expense and control goals; and

     * improved efficiency measures to better than targeted levels.

     The Chief Executive  Officer's  receipt,  pursuant to the 1995 Stock Option
Plan of  192,090  nonqualified  stock  options in  January  1998 was  related to
achievement of the 1997 corporate performance measures listed above. Compared to
the 1997 corporate objectives listed above, the Corporation:

     * met its targeted profitability objectives;

     * successfully  completed the  acquisition of ValliCorp  Holding,  Inc. and
       Valliwide  Bank,  and  successfully   assimilated   their  employees  and
       operations;

     * improved credit quality measures to better than established levels;

     * outperformed noninterest expense and control goals; and

     * improved efficiency measures to better than targeted levels.

     During  1997,  the  Corporation  and Mr.  Payne  agreed  to the  grant of a
nonqualified  pension in exchange for the cancellation of Mr. Payne's 1995, 1996
and 1997  restricted  performance  shares  because the pension,  with the longer
vesting  schedule,  provides the corporation  with a better retention device and
Mr. Payne will receive a level stream of income for 20 years.

     Other.  In 1993,  the  Internal  Revenue  Code  ("IRC")  was amended to add
section  162(m).  Section  162(m)  places a limit of $1,000,000 on the amount of
compensation that may be deducted by the Corporation in any year with respect to
certain of the Corporation's  highest paid executives.  The Corporation  intends
generally to qualify  compensation paid to executive  officers for deductibility
under  the  IRC,  including  section  162(m),  but  reserves  the  right  to pay
compensation that is not deductible under section 162(m).

     The  Employee  Benefits  and  Compensation   Committee  believes  that  the
foregoing  compensation  programs and  policies  provide  competitive  levels of
compensation,  encourage long-term  performance and promote management retention
while  further  aligning   shareholders'  and  managements'   interests  in  the
performance of the Corporation and the Corporation's Common Stock.


                                       11


     Members  of  the Employee Benefits and Compensation Committee as of January
25,  1999  are: P. D. Lynch, Chairman, E. Allen, D. Emerson, R. A. Nelson and M.
J. Ryan, Jr.


[The following  descriptive  data is supplied in accordance  with Rule 304(d) of
Regulation S-T]


                                                   Period Ending
                             ---------------------------------------------------------
Index                       12/31/93  12/31/94  12/31/95  12/31/96  12/31/97  12/31/98
- --------------------------------------------------------------------------------------
                                                                 
Westamerica Bancorporation    100.00    111.54    165.63    225.34    405.18    444.10
S&P 500                       100.00    101.32    139.39    171.26    228.42    293.69
Western Bank Monitor          100.00    103.32    147.54    182.99    335.73    352.51


<FN>
(1)  Assumes  $100  invested on December  31, 1993 in the  Corporation's  Common
     Stock,  the S&P 500 composite stock index and SNL Securities'  Western Bank
     Monitor index, with reinvestment of dividends.

(2)  Source: SNL Securities.
</FN>



                              APPROVAL OF AUDITORS

     The Board has selected KPMG LLP as independent  auditor for the Corporation
for the 1999 fiscal year, subject to the approval of the shareholders.  KPMG LLP
has informed the Corporation that it has had no connection during the past three
years with the  Corporation  or its  subsidiaries  in the  capacity of promoter,
underwriter, voting trustee, director, officer or employee.

     Representatives  of KPMG  LLP  will be  present  at the  Meeting  with  the
opportunity  to make a  statement  if they  desire  to do so and to  respond  to
appropriate questions.


                                       12


                                  OTHER MATTERS

     Management of the Corporation  does not know of any matters to be presented
at the Meeting other than those  specifically  referred to herein.  If any other
matters  should  properly  come  before  the  Meeting  or  any  postponement  or
adjournment  thereof,  the persons  named in the  enclosed  proxy intend to vote
thereon in accordance with their best business judgment.

     For a matter to be properly  brought  before the Meeting by a  shareholder,
section 2.02 of the  Corporation's  Bylaws  ("Section  2.02")  provides that the
shareholder must deliver or mail a written notice to the Secretary (or Assistant
Secretary) of the  Corporation not less than 14 days nor more than 50 days prior
to the Meeting.  Section 2.02 also provides that the notice must set forth as to
each matter that the  shareholder  proposes to bring  before the Meeting a brief
description  of the  business  desired to be brought  before the Meeting and the
reasons for  conducting  such  business at the Meeting,  the name and  residence
address of the shareholder proposing such business,  the number of shares of the
Corporation's  common stock that are owned by the  shareholder  and any material
interest of the shareholder in such business.

     The cost of the  solicitation of proxies in the  accompanying  form will be
borne by the Corporation. The Corporation has retained the services of Corporate
Investor Communications,  Inc. to assist in the proxy distribution at a cost not
to exceed $2,000 plus reasonable  out-of-pocket  expenses.  The Corporation will
reimburse  banks,  brokers and others  holding  stock in their names or names of
nominees or otherwise for reasonable  out-of-pocket expenses incurred in sending
proxies and proxy materials to the beneficial owners of such stock.



                                        BY ORDER OF THE BOARD OF DIRECTORS

                                        /s/ Kris Irvine

                                        Kris Irvine
                                        Assistant Corporate Secretary


Dated: March 17, 1999

                                       13


                                                                      APPENDIX A

- --------------------------------------------------------------------------------
PROXY                      WESTAMERICA BANCORPORATION                      PROXY
             PROXY SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS OF
                           WESTAMERICA BANCORPORATION

           For the Annual Meeting of Shareholders on April 21, 1999


     The undersigned  holder hereby  authorizes A. Latno,  Jr., R. Nelson and E.
Sylvester,  each with full power of  substitution,  to  represent  and vote,  as
designated  on the  reverse  side,  all  shares of Common  Stock of  Westamerica
Bancorporation  which the  undersigned  would be  entitled to vote at the Annual
Meeting of Shareholders of said  corporation to be held at the Fairfield  Center
for Creative Arts,  Fairfield,  California at 2:00 p.m. on Wednesday,  April 21,
1999, upon the matters set forth on the reverse side of this Proxy and described
in the accompanying Proxy Statement and upon such other business as may properly
come before the meeting or any postponement or adjournment thereof.

     This Proxy, when properly executed, will be voted as directed herein by the
undersigned shareholder.  If no direction is indicated, this Proxy will be voted
FOR all nominees and FOR Proposal 2.

             Please Mark, Sign, Date and Mail This Proxy Promptly,
                          Using the Enclosed Envelope.

- -----------------------------
  COMMENTS/ADDRESS CHANGE

                 (Continued, and to be signed on the other side)
- --------------------------------------------------------------------------------
 
                            - FOLD AND DETACH HERE -

                      MEETING TICKET REQUEST INSTRUCTIONS


                           Westamerica Bancorporation
                         Annual Meeting of Shareholders


                      2:00 P.M., Wednesday, April 21, 1999


                       Fairfield Center for Creative Arts
                             Fairfield, California

You can avoid registration lines by obtaining tickets in advance. If you plan to
attend the Meeting, please mark the "I Plan to Attend Meeting" box on your Proxy
and return it in the  enclosed  pre-addressed  return  envelope  to  Westamerica
Bancorporation,  c/o ChaseMellon Shareholder Services, Proxy Processing,  Church
St. Station, P.O. Box 1520, New York, NY 10277-1520. You will be mailed a ticket
entitling admission for two people.


- --------------------------------------------------------------------------------

Because of seating limitations,  your ticket is valid for admission of up to two
people. If you desire additional tickets, please call Westamerica Bancorporation
at (707) 863-6809.



                     Do not return this card with your Proxy





- ------------------------------------------------------------------------------------------------------------------------------------
                                                                                                       
        The Board of Directors recommends a vote FOR Proposals 1 and 2.                                     Please mark         [X]
                                                                                                           your votes as
                                                                                                            indicated in
                                                                                                            this example

                                            WITHHOLD  WITHHOLD
                                              FOR       FOR
                                     FOR      ALL   INDIVIDUAL(S)                                        FOR    AGAINST    ABSTAIN

1. Election of Directors--Nominees   [  ]     [  ]      [  ]          2. Approval of Auditors             [  ]     [  ]      [  ]

01 E. Allen          08 P. Mon Pere
02 L. Bartolini      09 R. Nelson                                     I PLAN TO ATTEND  MEETING
03 D. Emerson        10 C. Otto                                   If you check  this box to the right                        [  ]
04 L. Herwaldt       11 D. Payne                                 an admission card will be sent to you.
05 A. Latno, Jr.     12 M. Ryan, Jr.
06 P. Lynch          13 E. Sylvester
07 C. MacMillan

- --------------------------------
Except Nominee(s) written above

- ------------------------------------------------------------------------------------------------------------------------------------
                            *** IF YOU WISH TO VOTE BY TELEPHONE, PLEASE READ THE INSTRUCTIONS BELOW ***
- ------------------------------------------------------------------------------------------------------------------------------------

                                                                                                   DATE     /    /1999
                                                                                                        ----------------------------

                                                                               -----------------------------------------------------
                                                                               Signature


                                                                               -----------------------------------------------------
                                                                               Signature, if Jointly Held


                                                                               Please  sign  exactly as name  appears  hereon.  If
                                                                               acting as attorney,  executor,  trustee or in other
                                                                               representative  capacity,   please  sign  name  and
                                                                               title.  Receipt is hereby acknowledged of the Proxy
                                                                               Statement for the Meeting.

- ------------------------------------------------------------------------------------------------------------------------------------
                                                      - FOLD AND DETACH HERE --

                                VOTE BY TELEPHONE


                        QUICK - - - EASY - - - IMMEDIATE


Your telephone vote authorizes the named proxies to vote your shares in the same
manner as if you marked, signed and returned your proxy card.

*  You will be asked to enter a Control  Number  which is  located in the box in
   the lower right hand corner of this form.

- --------------------------------------------------------------------------------
OPTION #1: To vote  as  the  Board of Directors recommends on ALL proposals:
              Press 1.
- --------------------------------------------------------------------------------

               When asked, please confirm your vote by Pressing 1.
- --------------------------------------------------------------------------------
OPTION #2. If you choose to vote on each proposal separately,  press 0. You will
           hear these instructions:
- --------------------------------------------------------------------------------

 Proposal 1: To vote FOR ALL  nominees,  press 1; to WITHHOLD FOR ALL  nominees,
             press 9.

             To  WITHHOLD FOR INDIVIDUAL  nominee(s),  press 0 and listen to the
             instructions.

 Proposal 2: To vote FOR, press 1; AGAINST, press 9; ABSTAIN, press 0.

               When asked, please confirm your vote by Pressing 1.


- --------------------------------------------------------------------------------
          PLEASE DO NOT RETURN THE ABOVE PROXY CARD IF VOTED BY PHONE.
- --------------------------------------------------------------------------------

*  You will  then be asked if you plan to  attend  the  Meeting.  If you plan to
   attend,  press 1; you will be sent an admission  card.  If you do not plan to
   attend, press 0.

                Call - - Toll Free - - On a Touch Tone Telephone

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                                                                      APPENDIX B

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PROXY                      WESTAMERICA BANCORPORATION                      PROXY
                              VOTING INSTRUCTIONS
        TO THE TRUSTEE SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS OF
                           WESTAMERICA BANCORPORATION

           For the Annual Meeting of Shareholders on April 21, 1999


     The undersigned  holder hereby  authorizes and instructs the Trustee of the
Westamerica Bancorporation Tax Deferred Savings/Retirement Plan to represent and
vote,  as  designated   below,   all  shares  of  Common  Stock  of  Westamerica
Bancorporation  which the  undersigned  would be  entitled to vote at the Annual
Meeting of Shareholders of said  corporation to be held at the Fairfield  Center
for Creative Arts,  Fairfield,  California at 2:00 p.m. on Wednesday,  April 21,
1999 and any postponement or adjournment thereof.

     These voting instructions to the Trustee,  when properly executed,  will be
voted as directed herein by the undersigned shareholder.  If no instructions are
received,  the Trustee will vote all of the shares for which you are entitled to
provide  instruction in the same proportion as shares for which instructions are
received.  The Trustee may vote  according to its discretion on any other matter
which may properly come before the meeting.


      Please Mark, Sign, Date and Mail These Voting Instructions Promptly,
                          Using the Enclosed Envelope.

                 (Continued, and to be signed on the other side)
- --------------------------------------------------------------------------------

                           - FOLD AND DETACH HERE --


                               [GRAPHIC OMITTED]


                                                                  March 17, 1999
Dear Participant:


     As  a  participant   in  the   Westamerica   Bancorporation   Tax  Deferred
Savings/Retirement Plan (the "Plan"), you have an interest in the Annual Meeting
of Shareholders of Westamerica  Bancorporation  which will be held on Wednesday,
April 21,  1999 (the  "Meeting").  You may direct the Trustee of the Plan how to
vote all full and fractional shares of Westamerica Bancorporation stock standing
to the credit of your individual  account(s) (from the  Supplemental  Retirement
Plan Account,  Employer Matching Contributions and Employee Contributions) as of
February 26, 1999.

     For your  information,  we have enclosed a copy of the Proxy  Statement and
the Annual Report supplied to shareholders  of Westamerica  Bancorporation.  The
enclosed  Proxy  Statement  describes  two  proposals  to be  voted  on  by  the
shareholders  of  Westamerica  Bancorporation  at  the  Meeting.  The  Board  of
Directors of Westamerica Bancorporation recommends a vote FOR PROPOSALS 1 AND 2.
Please  instruct the Trustee how to vote on these  proposals by indicating  your
selection on the above Proxy.

     If the Trustee does not receive  written  instructions  from you before the
close of  business on April 13,  1999,  it will vote all of the shares for which
you are entitled to provide  instruction  in the same  proportion  as shares for
which  instructions  are received.  Under the terms of the Plan, with respect to
fractional  shares in plan  accounts  (from  the  Supplemental  Retirement  Plan
Account,  Employer  Matching  Contributions  and  Employee  Contributions),  the
Trustee may pool the results of instructions  received from all  participants to
whom fractional shares have been allocated and vote such shares accordingly.

     The Trustee  may also use its  discretion  in voting on any other  business
which may  properly  be  brought  before the  Meeting  (or any  postponement  or
adjournment  thereof) that was not specified in the Notice of Annual  Meeting of
Shareholders.  Please  instruct  the Trustee how to vote your  shares.  A return
envelope is enclosed for your convenience.

                                     Sincerely yours,

                                     /s/ Kris Irvine

                                     Kris Irvine
                                     Assistant Corporate Secretary



                                                                      APPENDIX C

  M         WESTAMERICA BANCORPORATION
  E                                         
  E         Attn: Corporate Secretary, A-2M  
  T         P.O. Box 1200                                              
  I         Suisun City, CA 94585-1200      
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