HIV incidence remains unacceptably high for adolescent girls and young women (AGYW). Pre-exposure prophylaxis (PrEP) HIV prevention tools are promising, with tenofovir (TFV)-based daily oral PrEP and the dapivirine vaginal ring (DPV-VR) recommended by WHO for cisgender women at-risk for HIV. Kenya is a leader for PrEP delivery in Africa and efforts are ongoing to increase PrEP access with AGYW as a priority group. Our team pioneered integrated PrEP delivery in family planning (FP) clinics in Kenya; yet, 40% of Kenyan women access contraception without interfacing with facilities, including at retail pharmacies, and would be missed by facility-based PrEP platforms. Retail pharmacies can increase options for reaching at-risk individuals with PrEP and efforts are underway to define pathways for pharmacy-delivered PrEP in Kenya. We adapted our FP clinic- based PrEP model and piloted PrEP delivery facilitated by nurse-navigators for AGYW seeking contraception at pharmacies. AGYW offered daily oral PrEP frequently initiated, planned to continue use, and were willing to pay for PrEP at pharmacies. Pill burden was a common reason for declining oral PrEP and could be addressed by offering DPV-VR. Through close collaboration with the Kenya Ministry of Health both, national- and county-level, we propose a cluster RCT at 20 pharmacies in Kisumu, Kenya–a region with an HIV prevalence of up to 28% among women–to test the effectiveness of utilizing nurse-navigators at retail pharmacies to enhance AGYW PrEP use. We will expand on our successful pilot to offer both daily oral PrEP and the DPV-VR and prospectively ascertain PrEP outcomes (initiation, persistence, adherence) among AGYW. This effectiveness-implementation hybrid RCT is designed to expedite translation into practice by evaluating clinical effectiveness alongside implementation and cost outcomes. We hypothesize that combining nurse-navigators with pharmacy-based PrEP will provide a cost-effective strategy for delivering novel HIV prevention tools to AGYW in HIV high-burden settings. Aim 1 will determine the effect of nurse-navigators on PrEP initiation, persistence, and adherence among AGYW seeking contraception within a pharmacy-based PrEP delivery model through a 2-arm cluster RCT among HIV-negative AGYW at 20 retail pharmacies in Kisumu, Kenya. AGYW seeking contraception will be offered PrEP and self-select daily oral PrEP or the DVR-VR. Primary outcomes will be proportion of AGYW accessing contraception that initiate PrEP, persist with use at 10 mos., and adhere (quantified by TFV or DPV hair levels). Secondary outcomes will include PrEP selection (PrEP pills vs. DPV-VR), STI incidence, and adherence cofactors. Aim 2 will identify potential barriers and facilitators to acceptability, feasibility, and client satisfaction of nurse-navigators and DPV-VR delivery for AGYW accessing PrEP at retail pharmacies through a qualitative evaluation guided by Proctor et al. Aim 3 will estimate the cost-effective...