SmartStop Self Storage REIT, Inc.

Disclosure Controls and Procedures

We maintain disclosure controls and procedures to ensure that information required to be disclosed in the reports we file pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), are recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC, and that such information is accumulated and communicated to management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow timely decisions regarding required disclosure based on the definition of “disclosure controls and procedures” in Rule 13a-15(e) of the Exchange Act. In designing and evaluating the disclosure controls and procedures, we recognize that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, as ours are designed to do, and we necessarily are required to apply our judgment in evaluating whether the benefits of the controls and procedures that we adopt outweigh their costs.

As of the end of the period covered by this report, management, including our Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of the design and operation of our disclosure controls and procedures. Based upon this evaluation, our Chief Executive Officer and Chief Financial Officer concluded that the disclosure controls and procedures were effective at the reasonable assurance level as of the end of the period covered by this report to ensure that information required to be disclosed in the reports we file and submit under the Exchange Act is recorded, processed, summarized and reported as and when required.

Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for us. Our management, including our Chief Executive Officer and Chief Financial Officer, evaluated, as of December 31, 2025, the effectiveness of our internal control over financial reporting using the framework in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on that evaluation, our management concluded that our internal control over financial reporting was effective as of December 31, 2025.

There have been no changes in our internal control over financial reporting that occurred during the quarter ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

In accordance with guidance issued by the SEC, companies are permitted to exclude acquisitions from their assessment of internal control over financial reporting for a period of no longer than one year from the date of the acquisition. We completed the acquisition of Argus effective October 1, 2025. As the acquisition occurred during the fourth quarter of 2025, management excluded Argus from its assessment of the effectiveness of our internal control over financial reporting as of December 31, 2025. Argus constituted approximately 1% of our consolidated total assets and 2% of our consolidated total revenues as of and for the year ended December 31, 2025. Management will include Argus as a part of management’s next assessment of internal control over financial reporting as of December 31, 2026. See Note 4 – Third Party Platform Acquisition of the Notes to the Consolidated Financial Statements for further discussion of the Argus acquisition.

Attestation Report of the Independent Registered Public Accounting Firm

BDO USA, P.C., an independent registered public accounting firm, has audited our consolidated financial statements and has issued the following report on the effectiveness of our internal control over financial reporting:

Report of Independent Registered Public Accounting Firm

Shareholders and Board of Directors

Ladera Ranch, California

Opinion on Internal Control over Financial Reporting

We have audited SmartStop Self Storage REIT, Inc.’s (the “Company’s”) internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (the “COSO criteria”). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated balance sheets of the Company as of December 31, 2025 and 2024, the related consolidated statements of operations, comprehensive income (loss), equity and temporary equity, and cash flows for each of the three years in the period ended December 31, 2025, and the related notes and financial statement schedule and our report dated February 27, 2026 expressed an unqualified opinion thereon.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Item 9A, Internal Control Over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit of internal control over financial reporting in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audit also included performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

As indicated in the accompanying Item 9A, Internal Control Over Financial Reporting, management’s assessment of and conclusion on the effectiveness of internal control over financial reporting did not include the internal controls of Argus Professional Storage Management, LLC (“Argus”), which was acquired on October 1, 2025, and which is included in the consolidated balance sheets of the Company as of December 31, 2025, and the related consolidated statements of operations, comprehensive income (loss), equity and temporary equity, and cash flows for the year then ended. Argus constituted 1% total assets as of December 31, 2025 and 2% of revenues for the year then ended. Management did not assess the effectiveness of internal control over financial reporting of Argus because of the timing of the acquisition which was completed on October 1, 2025. Our audit of internal control over financial reporting of the Company also did not include an evaluation of the internal control over financial reporting of Argus.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/ BDO USA, P.C.

Costa Mesa, California

February 27, 2026