Westamerica Bank

January 23, 2006

For Immediate Release


San Rafael, CA: Westamerica Bancorporation (NASDAQ: WABC), is scheduled to participate in the Citigroup Financial Services Conference to be held January 31 - February 1, 2006 at The Waldorf Astoria in New York City.

David L. Payne, Chairman, President and CEO, will make a presentation beginning at 10:45 a.m. ET on Tuesday, 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/fs2006/38104399.cfm

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.