Exhibit 99.3
CASTOR MARITIME INC. 223 CHRISTODOULOU
CHATZIPAVLOU STREET HAWAIIROYAL GARDENS 3036 LIMASSOL, CYPRUS SCAN TO VIEW MATERIALS & VOTE VOTE BY INTERNET - www.proxyvote.com
or scan the QR Barcode above Use the Internet to transmit your voting instructions and for
electronic delivery of information. Vote by 11:59 P.M. ET on September 11, 2025. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form.
ELECTRONIC DELIVERY OF FUTURE PROXY MATERIALS If you would like to reduce the costs incurred by
our company in mailing proxy materials, you can consent to receiving all future proxy statements, proxy cards and annual reports electronically via e-mail or the Internet. To sign up for electronic delivery, please follow the instructions
above to vote using the Internet and, when prompted, indicate that you agree to receive or access proxy materials electronically in future years. VOTE BY PHONE
- 1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions. Vote by 11:59 P.M. ET on September 11, 2025. Have your proxy card in hand when you call and
then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it in
the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717.TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: V76968-P36585 KEEP THIS PORTION FOR YOUR RECORDS THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. DETACH AND RETURN THIS PORTION ONLY CASTOR MARITIME INC. The Board of Directors recommends you vote FOR the nominee listed in proposal 1: 1. THE ELECTION OF CLASS B DIRECTOR TO SERVE UNTIL THE 2028 ANNUAL MEETING OF SHAREHOLDERS: Nominee: 1a. Dionysios Makris The Board of
Directors recommends you vote FOR proposal 2: 2. To approve the
appointment of Deloitte Certified Public Accountants S.A., as the Company's independent auditors for the fiscal year of 2025. For Against Abstain NOTE: Such other business as may properly come before the meeting or any adjournment thereof.
Please sign exactly as your name(s) appear(s) hereon. When signing as attorney, executor, administrator, or other fiduciary, please give full title as such. Joint owners should each sign personally. All holders must sign. If a corporation or
partnership, please sign in full corporate or partnership name by authorized officer. Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date
Important Notice Regarding the Availability of
Proxy Materials for the Annual Meeting: The Notice and Proxy Statement is available at www.proxyvote.com CASTOR MARITIME INC. Proxy for Annual Meeting of Shareholders on September 12, 2025 Solicited on Behalf of the Board of Directors The
undersigned hereby appoints Petros Panagiotidis with full power of substitution and power to act alone, as proxy to vote all of the common shares which the undersigned would be entitled to vote if personally present and acting at the Annual
Meeting of Shareholders of Castor Maritime Inc., to be held at 223 Christodoulou Chatzipavlou Street, Hawaii Royal Gardens, 3036 Limassol, Cyprus, on September 12, 2025 at 6:00 p.m. local time, and at any adjournments or postponements
thereof. This proxy, when properly executed, will be voted in the manner directed herein. If no such direction is made, this proxy will be voted in accordance with
the Board of Directors' recommendations. Continued and to be signed on reverse side