Long-acting injectable Cabotegravir (CAB-LA) for HIV pre-exposure prophylaxis (PrEP) is recommended by the World Health Organization. ImPrEP CAB Brasil is an implementation study with the objective of generating critical evidence on feasibility, acceptability, and effectiveness of incorporating CAB-LA PrEP into existing oral PrEP public services offered to cisgender men and transgender or non-binary individuals. Site preparedness activities were developed to enable implementation. ImPrEP conducted sub-studies aiming to: a) assess HIV seroincidence rates among target population; b) evaluate the secondary distribution of HIV self-tests to generate demand for PrEP services, c) explore PrEP preferences; d) streamline procedures for participants’ eligibility and CAB LA injection and to finalize an mHealth counseling tool. The ImPrEP CAB Brasil will design programmatic strategies to implement and scale up feasible, equitable, cost-effective, sustainable, and comprehensive PrEP programs.