WESTAMERICA BANCORPORATION

**UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

The Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

Westamerica Bancorporation

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

**1108 Fifth Avenue

To Our Shareholders:

You are cordially invited to attend the Annual Meeting of Shareholders of Westamerica Bancorporation. It will be held at10:00 a.m. Pacific Time on Thursday, April 23, 2026, at Westamerica Bancorporation, 4550 Mangels Blvd., Fairfield, California as stated in the formal notice accompanying this letter. We hope you will plan to attend.

At the Annual Meeting, the shareholders will be asked to (i) elect eight directors; (ii) approve a non-binding advisory vote on the compensation of our named executive officers; (iii) ratify the selection of the independent auditor; and (iv) conduct other business that may properly come before the Annual Meeting.

In order to ensure your shares are voted at the Annual Meeting, you can vote through the internet, by telephone or by mail. Instructions regarding internet and telephone voting are included on the Proxy Card. If you elect to vote by mail, please sign, date and return the Proxy Card in the accompanying postage-paid envelope. The Proxy Statement explains more about voting in the section entitled “Voting Information – How You Can Vote.”

We look forward to seeing you at the Annual Meeting.

Sincerely,

David L. Payne

Chairman of the Board, President

and Chief Executive Officer

WESTAMERICA BANCORPORATION

1108 Fifth Avenue

NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

Items of Business

Management’s eight nominees are listed and described in the attached proxy statement.

Who Can Vote?

Shareholders of record at the close of business on March 4, 2026 are entitled to notice of, and to vote at, the Annual Meeting or any postponement or adjournment thereof.

Admission to the Annual Meeting

No ticket will be necessary for admission to the Annual Meeting. However, to facilitate the admission process, shareholders of record planning to attend the Annual Meeting should check the appropriate box on the Proxy Card. Your name will be added to a list of attendees. If you hold shares through an intermediary, such as a bank or broker, you may need to register at the desk in the lobby. Please bring the following as evidence of ownership: 1) a legal proxy, or your brokerage statement dated on or after March 4, 2026, evidencing your ownership on March 4, 2026, the record date; and 2) photo identification.

Annual Report

Westamerica Bancorporation’s Annual Report on Form 10-K (“Annual Report”) to shareholders for the fiscal year ended December 31, 2025 is enclosed or is available for viewing as indicated on the Shareholder Meeting Notice and on the Company’s website at: www.westamerica.com, under “Shareholders.” The Annual Report contains financial and other information about the activities of Westamerica Bancorporation, but does not constitute a part of the proxy soliciting materials.

Important notice regarding the availability of proxy materials for the shareholder meeting being held on

Thursday, April 23, 2026:

**The Proxy Statement and the Annual Report on Form 10-K are available at:**www.westamerica.com.

YOUR VOTE IS IMPORTANT PLEASE COMPLETE, SIGN, DATE AND PROMPTLY RETURN YOUR PROXY, OR VOTE BY TELEPHONE OR ONLINE USING THE PROCEDURES DESCRIBED IN THE PROXY STATEMENT.

TABLE OF CONTENTS

WESTAMERICA BANCORPORATION

1108 Fifth Avenue

PROXY STATEMENT