ANNUAL MEETING OF SHAREHOLDERS OF CUBESMART May 17, 2022 Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on May 17, 2022. The proxy statement and 2021 Annual Report to Shareholders are available at http://investors.cubesmart.com/sec-filings/documents/default.aspx Please sign, date and mail your proxy card in the envelope provided as soon as possible. Signature of Shareholder Date: Signature of Shareholder Date: Note: Please sign exactly as your name or names appear on this Proxy. When shares are held jointly, each holder should sign. When signing as executor, administrator, attorney, trustee or guardian, please give full title as such. If the signer is a corporation, please sign full corporate name by duly authorized officer, giving full title as such. If signer is a partnership, please sign in partnership name by authorized person. To change the address on your account, please check the box at right and indicate your new address in the address space above. Please note that changes to the registered name(s) on the account may not be submitted via this method. 1. Election of Trustees: O Piero Bussani O Dorothy Dowling O John W. Fain O Jair K. Lynch O Christopher P. Marr O Deborah Ratner Salzberg O John F. Remondi O Jeffrey F. Rogatz 2. To ratify the appointment of KPMG LLP as our independent registered public accounting firm for the year ending December 31, 2022; 3. To cast an advisory vote to approve our executive compensation; To transact such other business as may properly come before the meeting or any adjournment or postponement of the meeting. In their discretion, the proxies are authorized to vote upon such other matters as may properly come before this meeting. If this proxy card is properly executed and returned to the Company, the attorney-in-fact and proxy will vote all of the undersigned's shares entitled to vote on the matters hereon as directed hereon or, where no direction is indicated, the undersigned's vote will be cast FOR each of the matters hereon. The attorney-in-fact and proxy will vote such shares as recommended by the Board of Trustees, or, if no recommendation is given, in his own discretion, with regard to any other matters as may properly come before the meeting, including any proposal to adjourn or postpone the meeting. FOR AGAINST ABSTAIN FOR ALL NOMINEES WITHHOLD AUTHORITY FOR ALL NOMINEES FOR ALL EXCEPT (See instructions below) INSTRUCTIONS: To withhold authority to vote for any individual nominee(s), mark “FOR ALL EXCEPT” and fill in the circle next to each nominee you wish to withhold, as shown here: NOMINEES: THE BOARD OF TRUSTEES RECOMMENDS A VOTE "FOR" THE ELECTION OF TRUSTEES AND "FOR" PROPOSALS 2 AND 3. PLEASE SIGN, DATE AND RETURN PROMPTLY IN THE ENCLOSED ENVELOPE. PLEASE MARK YOUR VOTE IN BLUE OR BLACK INK AS SHOWN HERE x Please detach along perforated line and mail in the envelope provided. ------------------ ---------------- 20833000000000000000 1 051722 GO GREEN e-Consent makes it easy to go paperless. With e-Consent, you can quickly access your proxy material, statements and other eligible documents online, while reducing costs, clutter and paper waste. Enroll today via www.astfinancial.com to enjoy online access.

Signature of Shareholder Date: Signature of Shareholder Date: Note: Please sign exactly as your name or names appear on this Proxy. When shares are held jointly, each holder should sign. When signing as executor, administrator, attorney, trustee or guardian, please give full title as such. If the signer is a corporation, please sign full corporate name by duly authorized officer, giving full title as such. If signer is a partnership, please sign in partnership name by authorized person. To change the address on your account, please check the box at right and indicate your new address in the address space above. Please note that changes to the registered name(s) on the account may not be submitted via this method. INSTRUCTIONS: To withhold authority to vote for any individual nominee(s), mark “FOR ALL EXCEPT” and fill in the circle next to each nominee you wish to withhold, as shown here: JOHN SMITH 1234 MAIN STREET APT. 203 NEW YORK, NY 10038 ANNUAL MEETING OF SHAREHOLDERS OF CUBESMART May 17, 2022 INTERNET - Access “www.voteproxy.com” and follow the on-screen instructions or scan the QR code with your smartphone. Have your proxy card available when you access the web page. TELEPHONE - Call toll-free 1-800-PROXIES (1-800-776-9437) in the United States or 1-718-921-8500 from foreign countries from any touch-tone telephone and follow the instructions. Have your proxy card available when you call. Vote online/phone until 11:59 PM EST the day before the meeting. MAIL - Sign, date and mail your proxy card in the envelope provided as soon as possible. IN PERSON - You may vote your shares in person by attending the Annual Meeting. GO GREEN - e-Consent makes it easy to go paperless. With e-Consent, you can quickly access your proxy material, statements and other eligible documents online, while reducing costs, clutter and paper waste. Enroll today via www.astfinancial.com to enjoy online access. PROXY VOTING INSTRUCTIONS Please detach along perforated line and mail in the envelope provided IF you are not voting via telephone or the Internet. THE BOARD OF TRUSTEES RECOMMENDS A VOTE "FOR" THE ELECTION OF TRUSTEES AND "FOR" PROPOSALS 2 AND 3. PLEASE SIGN, DATE AND RETURN PROMPTLY IN THE ENCLOSED ENVELOPE. PLEASE MARK YOUR VOTE IN BLUE OR BLACK INK AS SHOWN HERE x ------------------ ---------------- 20833000000000000000 1 051722 COMPANY NUMBER ACCOUNT NUMBER Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on May 17, 2022. The proxy statement and 2021 Annual Report to Shareholders are available at http://investors.cubesmart.com/sec-filings/documents/default.aspx 1. Election of Trustees: O Piero Bussani O Dorothy Dowling O John W. Fain O Jair K. Lynch O Christopher P. Marr O Deborah Ratner Salzberg O John F. Remondi O Jeffrey F. Rogatz 2. To ratify the appointment of KPMG LLP as our independent registered public accounting firm for the year ending December 31, 2022; 3. To cast an advisory vote to approve our executive compensation; To transact such other business as may properly come before the meeting or any adjournment or postponement of the meeting. In their discretion, the proxies are authorized to vote upon such other matters as may properly come before this meeting. If this proxy card is properly executed and returned to the Company, the attorney-in-fact and proxy will vote all of the undersigned's shares entitled to vote on the matters hereon as directed hereon or, where no direction is indicated, the undersigned's vote will be cast FOR each of the matters hereon. The attorney-in-fact and proxy will vote such shares as recommended by the Board of Trustees, or, if no recommendation is given, in his own discretion, with regard to any other matters as may properly come before the meeting, including any proposal to adjourn or postpone the meeting. FOR AGAINST ABSTAIN FOR ALL NOMINEES WITHHOLD AUTHORITY FOR ALL NOMINEES FOR ALL EXCEPT (See instructions below) NOMINEES:

0 ------------------ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ---------------- 14475 CUBESMART Proxy for Annual Meeting of Shareholders on May 17, 2022 Solicited on Behalf of the Board of Trustees The undersigned hereby appoints Christopher P. Marr, Timothy M. Martin, and Jeffrey P. Foster, and each of them, as attorney-in-fact and proxy with full power of substitution to represent the undersigned and to vote all of the Common Shares of the Company, held of record by the undersigned on March 15, 2022, at the Annual Meeting of Shareholders to be held on Tuesday, May 17, 2022, at 8:00 a.m., Eastern Daylight Saving time, at Cubesmart, 5 Old Lancaster Road, Malvern, PA 19355, and at any adjournment or postponement thereof. Said attorney-in-fact and proxy is instructed to vote as directed on the reverse side. For more information on how to obtain directions to be able to attend the annual meeting and/or vote in person at the annual meeting please see the accompanying proxy statement or contact our Secretary at 610-535-5000. The undersigned acknowledges receipt of the accompanying Notice of Annual Meeting of Shareholders and Proxy Statement. (Continued and to be signed on the reverse side.) 1.1

1. Election of Trustees: Piero Bussani Dorothy Dowling John W. Fain Jair K. Lynch Christopher P. Marr Deborah Ratner Salzberg John F. Remondi Jeffrey F. Rogatz 2. To ratify the appointment of KPMG LLP as our independent registered public accounting firm for the year ending December 31, 2022; 3. To cast an advisory vote to approve our executive compensation; To transact such other business as may properly come before the meeting or any adjournment or postponement of the meeting. In their discretion, the proxies are authorized to vote upon such other matters as may properly come before this meeting. THE BOARD OF TRUSTEES RECOMMENDS A VOTE "FOR" THE ELECTION OF TRUSTEES AND "FOR" PROPOSALS 2 AND 3. NOMINEES: Important Notice of Availability of Proxy Materials for the Shareholder Meeting of CUBESMART To Be Held On: May 17, 2022 at 8:00 a.m. at Cubesmart, 5 Old Lancaster Road, Malvern PA 19355 This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. If you want to receive a paper or e-mail copy of the proxy materials you must request one. There is no charge to you for requesting a copy. To facilitate timely delivery please make the request as instructed below before 5-3-2022. Please visit http://investors.cubesmart.com/sec-filings/documents/default.aspx, where the following materials are available for view: • Notice of Annual Meeting of Shareholders • Proxy Statement • Form of Electronic Proxy Card • Annual Report on Form 10-K TO REQUEST MATERIAL: TELEPHONE: 888-Proxy-NA (888-776-9962) 718-921-8562 (for international callers) E-MAIL: info@astfinancial.com WEBSITE: https://us.astfinancial.com/OnlineProxyVoting/ProxyVoting/RequestMaterials TO VOTE: ONLINE: To access your online proxy card, please visit www.voteproxy.com and follow the on-screen instructions or scan the QR code with your smartphone. You may enter your voting instructions at www.voteproxy.com up until 11:59 PM Eastern Time the day before the cut-off or meeting date. IN PERSON: You may vote your shares in person by attending the Annual Meeting. TELEPHONE: To vote by telephone, please visit www.voteproxy.com to view the materials and to obtain the toll free number to call. MAIL: You may request a card by following the instructions above. COMPANY NUMBER ACCOUNT NUMBER CONTROL NUMBER JOHN SMITH 1234 MAIN STREET APT. 203 NEW YORK, NY 10038 Please note that you cannot use this notice to vote by mail.