Westamerica Bank

October 16, 2007

For Immediate Release

San Rafael, CA: Westamerica Bancorporation (NASDAQ: WABC), parent company of Westamerica Bank, today reported net income of $22.0 million for the third quarter of 2007, compared to $22.4 million for the second quarter of 2007 and $24.2 million for the third quarter of 2006. Third quarter 2007 diluted earnings per share were $0.74, compared to $0.74 for the second quarter of 2007 and $0.77 for the third quarter of 2006. Return on average common equity (ROE) for the third quarter of 2007 was 21.7 percent and return on assets (ROA) was 1.89 percent.

For the first nine months of 2007, net income totaled $67.9 million, compared to $74.8 million for the same period in 2006. Diluted earnings per share were $2.24 for the first nine months of 2007, compared to $2.34 for the same period in 2006. For the first nine months of 2007, ROE was 22.2 percent and ROA was 1.95 percent.

“Our net interest margin was essentially stable in the third quarter of 2007, down only 0.02 percent from the prior quarter. We expect to begin realizing margin expansion as the September 2007 reduction in the federal funds rate causes interest rate re-pricing of our funding sources at a faster pace than our loans and investments,” said Chairman, President and CEO David Payne. “During the third quarter 2007, our credit quality remained stable in spite of the slowing economy. We have worked hard to achieve the seven percent increase in our non-interest revenues and four percent reduction in our expenses in the first nine months of 2007 compared to the same period last year,” added Payne.

Net interest income on a fully taxable equivalent (FTE) basis was $45.6 million in the third quarter of 2007 compared to $46.1 million and $50.2 million in the second quarter of 2007 and the third quarter of 2006, respectively. The third quarter of 2007 net interest margin (FTE) was 4.34 percent, down from 4.36 percent and 4.54 percent in the second quarter of 2007 and the third quarter of 2006, respectively.

Noninterest income for the first nine months of 2007 totaled $44.6 million, increased from $41.6 million in the first nine months of 2006. The $3.0 million increase is primarily due to:

$1.4 million increase in service charges on deposit accounts.
$800 thousand higher merchant credit card income.
$200 thousand increase in debit card and ATM fees.
$800 thousand gain from life insurance proceeds recognized in the first quarter of 2007.

Noninterest expense for the first nine months of 2007 was $74.2 million, reduced from $77.2 million for the first nine months of 2006. The $3.0 million decline is primarily due to:

$2.1 million lower personnel costs.
$500 thousand reduction in professional fees.
$300 thousand lower occupancy and equipment expense.
$300 thousand decline in amortization of intangible assets.
$300 thousand increase in data processing expenses.

The higher data processing expenses and a portion of the lower personnel costs are due to conversion of the Company's item processing function to an outside vendor. This conversion is not expected to change overall expenses by a meaningful amount. The FTE efficiency ratio (expenses divided by revenues) for the first nine months of 2007 was 40.5 percent, compared to 39.1 percent for the first nine months of 2006.

The provision for credit losses was $75 thousand for the third quarter of 2007, unchanged from the previous and year ago quarters.

At September 30, 2007, shareholders' equity was $404 million and the Company's total regulatory capital ratio was 10.7 percent, which exceeds the "well-capitalized" level of 10 percent under regulatory requirements. During the third quarter 2007, shares repurchased, net of shares issued, totaled 354 thousand shares. At September 30, 2007, 1.8 million shares remain authorized under the Company's stock repurchase plan.

Westamerica Bancorporation, through its wholly owned subsidiary Westamerica Bank, operates 87 branches throughout 21 Northern and Central California counties. At September 30, 2007, the company had total assets outstanding of $4.7 billion.

Quarterly Financial Highlights

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 June 30, 2007, and Form 10-K for the year ended December 31, 2006, 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, and 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.

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