Westamerica Bank

January 23, 2007

For Immediate Release

San Rafael, CA: Westamerica Bancorporation (NASDAQ: WABC), is scheduled to participate in the Citigroup Financial Services Conference to be held January 30-31, 2007 at The Waldorf Astoria in New York City.

David L. Payne, Chairman, President and CEO, will make a presentation beginning at 8:45 a.m. ET on Wednesday, January 31, followed by a question and answer session. Comments and the related slide presentation will be available via a live, listen-only Webcast. The presentation will also be available at:

http://www.veracast.com/webcasts/citigroup/fs07/72202303.cfm

As previously announced, Westamerica reported annual earnings for 2006 totaling $98.8 million, or $3.11 diluted earnings per share. For the year 2006, shareholder dividends totaled $1.30 per share, a seven percent increase over $1.22 per share for the year 2005.

Westamerica Bancorporation through its wholly owned subsidiary, Westamerica Bank, operates 87 branches and 2 trust offices throughout 21 Northern and Central California counties.