Exhibit 23.1 INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRMS' CONSENT We consent to the incorporation by reference in Registration Statements No. 333-104458 and 333-01649 of West Coast Bancorp on Form S-8 of our report dated June 25, 2004, appearing in this Annual Report on Form 11-K of the West Coast Bancorp 401(k) Plan for the year ended December 31, 2003. DELOITTE & TOUCHE LLP Portland, Oregon June 25, 2004