Westamerica Bank

January 20, 2004

For Immediate Release


San Rafael, CA: Westamerica Bancorporation (NASDAQ: WABC), is scheduled to participate in the Citigroup Smith Barney Financial Services Conference to be held January 27-29, 2004 at The Plaza Hotel in New York City.

David L. Payne, chairman, president and CEO, will make a presentation beginning at 3:45 p.m. EST on Tuesday, January 27, followed by a question and answer session. Comments and the related slide presentation will be available via a live, listen-only Webcast. Investors and the public can access the presentation via a webcast at:

http://www.veracast.com/webcasts/sbcitigroup/financial-services-2004/81109578.cfm

Westamerica Bancorporation through its wholly owned subsidiary, Westamerica Bank, operates 88 branches and 2 trust offices throughout 22 Northern and Central California counties.