Westamerica Bank

February 23, 2006

For Immediate Release


San Rafael, CA: Westamerica Bancorporation (NASDAQ: WABC) is scheduled to participate in the Keefe, Bruyette & Woods Regional Bank Conference to be held March 1-2, 2006 at Langham Hotel in Boston.

David L. Payne, Chairman, President and CEO, will make a presentation beginning at 10:15 a.m. ET on Thursday, March 2, followed by a question and answer session. Comments and the related slide presentation will be available via a live, listen-only Webcast. To listen, go to https://www.westamerica.com/investor_relations/press_rel_feb2306.html

and follow the links to the Webcast. The presentation will also be available at

http://www.kbw.com/news/conference_regional.html

As previously announced, Westamerica reported record annual earnings for 2005 totaling $107.4 million, or $3.27 diluted earnings per share. For the year 2005, shareholder dividends totaled $1.22 per share, an 11 percent increase over $1.10 per share for the year 2004.

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