1 EXHIBIT 23.5 CONSENT OF INDEPENDENT CERTIFIED PUBLIC ACCOUNTANTS We consent to the incorporation by reference in this Registration Statement on Form S-4, our report dated January 14, 1994 appearing in the Westamerica Financial Registration Statement on Form S-4 (File No. 33-55417) filed on October 5, 1994 with the Securities and Exchange Commission pursuant to the Securities Act of 1933. /s/ Grant Thornton LLP - ---------------------- Grant Thornton LLP Stockton, California February 6, 1995