Westamerica Bank

July 28, 2005

For Immediate Release


San Rafael, CA: The Board of Directors of Westamerica Bancorporation (NASDAQ: WABC), today declared a quarterly cash dividend of $0.30 cents per share on common stock outstanding to shareholders of record at the close of business on August 8, 2005 . The dividend is payable August 19, 2005.

As previously announced, Westamerica Bancorporation reported record quarterly earnings for the second quarter of 2005 of $27.9 million or $0.84 diluted earnings per share, compared with $24.6 million or $0.76 diluted earnings per share for the second quarter of 2004. Second quarter 2005 results include a property sale gain, which increased diluted earnings per share $0.03. The second quarter of 2005 represents the first full quarter of operations following the March 1, 2005 acquisition of Redwood Empire Bancorp.

Westamerica Bancorporation through its wholly owned subsidiary, Westamerica Bank, operates 88 branches and two trust offices throughout 21 Northern and Central California counties.



FORWARD-LOOKING INFORMATION:

The following appears in accordance with the Private Securities Litigation Reform Act of 1995:

This press release may contain forward-looking statements about the Company, including descriptions of plans or objectives of its management for future operations, products or services, and forecasts of its revenues, earnings or other measures of economic performance. Forward-looking statements can be identified by the fact that they do not relate strictly to historical or current facts. They often include the words "believe," "expect," "anticipate," "intend," "plan," "estimate," or words of similar meaning, or future or conditional verbs such as "will," "would," "should," "could," or "may."

Forward-looking statements, by their nature, are subject to risks and uncertainties. A number of factors - many of which are beyond the Company's control - could cause actual conditions, events or results to differ significantly from those described in the forward-looking statements. The Company's most recent annual and quarterly reports filed with the Securities and Exchange Commission, including the Company's Form 10-Q for the quarter ended March 31, 2005 and Form 10-K for the year ended December 31, 2004, describe some of these factors, including certain credit, market, operational, liquidity and interest rate risks associated with the Company's business and operations. Other factors described in these reports include changes in business and economic conditions, competition, fiscal and monetary policies, disintermediation, legislation including the Sarbanes-Oxley Act of 2002 and the Gramm-Leach-Bliley Act of 1999, the combination of the former Redwood Empire Bancorp and other mergers and acquisitions.

Forward-looking statements speak only as of the date they are made. The Company does not undertake to update forward-looking statements to reflect circumstances or events that occur after the date forward looking statements are made.

###