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Exhibit 31.2

CERTIFICATION UNDER
SECTION 302 OF
THE SARBANES OXLEY ACT OF 2002


I, Jennifer J. Finger, Chief Financial Officer of the registrant,
certify that:

1. I have reviewed this quarterly report for the period ending June 30, 2004 on
Form 10-Q of Westamerica Bancorporation;

2. Based on my knowledge, this quarterly report does not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements made, in light of the circumstances under which such statements
were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects the
financial condition, results of operations and cash flows of the registrant as
of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial
reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the
registrant and have:
  (a) Designed such disclosure controls and procedures, or caused such
  disclosure controls and procedures to be designed under our supervision, to
  ensure that material information relating to the registrant, including its
  consolidated subsidiaries, is made known to us by others within those
  entities, particularly during the period in which this report is being
  prepared;

  (b) Designed such internal control over financial reporting, or caused such
  internal control over financial reporting to be designed under our
  supervision, to provide reasonable assurance regarding the reliability of
  financial reporting and the preparation of financial statements for external
  purposes in accordance with generally accepted accounting principles;

  (c) Evaluated the effectiveness of the registrant's disclosure controls and
  procedures and presented in this report our conclusions about the
  effectiveness of the disclosure controls and procedures, as of the end of the
  period covered by this report based on such evaluation; and

  (d) Disclosed in this report any change in the registrant's internal control
  over financial reporting that occurred during the registrant's most recent
  fiscal quarter (the registrant's fourth fiscal quarter in the case of an
  annual report) that has materially affected, or is reasonably likely to
  materially affect, the registrant's internal control over financial
  reporting; and

5. The registrant's other certifying officer(s) and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to the
registrant's auditors and the audit committee of registrant's board of directors
(or persons performing the equivalent functions):
  (a) All significant deficiencies and material weaknesses in the design or
  operation of internal control over financial reporting which are easonably
  likely to adversely affect the registrant's ability to record, process,
  summarize and report financial information; and

  (b) Any fraud, whether or not material, that involves management or other
  employees who have a significant role in the registrant's internal control
  over financial reporting.





/s/  Jennifer J. Finger                              August 6, 2004
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Jennifer J. Finger                                   Date
Senior Vice President and Chief Financial Officer