Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Amendment No. 1 to the Registration Statement No. 333-290559 on Form S-3 of our report dated February 29, 2024 (March 3, 2025, as to the effects of the adoption of ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, described in Note 2) relating to the 2022 and 2023 financial statements of Quantum-Si Incorporated, appearing in the Annual Report on Form 10-K of Quantum-Si Incorporated for the year ended December 31, 2024. We also consent to the reference to us under the heading "Experts" in such Registration Statement.

/s/ Deloitte & Touche LLP

New York, New York

October 9, 2025