Introduction Community acceptability and sustainability of new HIV prevention methods remain key barriers to curb high HIV incidence rates for transgender women (TW) in Peru. Improved understanding of how geography, culture, and socialisation influence HIV-associated risks and uptake of new prevention technologies is critical to address the HIV epidemic among TW.

Methods In 2015–2016, 20 interviews and demographic surveys were conducted with TW in Peru to inform a social network-based PrEP adherence intervention. (Interviews probed on: socialisation, social network formations, preferred HIV intervention methods). Audio files were transcribed verbatim and analysed via immersion crystallisation using Dedoose software.

Results TW had a mean age of 30 years, 40% (n=8) reported sex work as their primary occupation, and 60% (n=12) had migrated from another part of Peru to Lima. Principal motivations for migration were: lack of economic opportunity, familial rejection due to gender identity, and seeking larger communities of TW as found in Lima. Co-habitation with other TW was common, underscoring cluster structures of socialisation, acculturation to existing norms (i.e., learning the rules of sex work in Lima), and knowledge-sharing. Among TW migrants, social network clusters were patterned not only on gender identity and occupation, but also province of origin (i.e., Iquitos, Trujillo) through which new arrivals would learn social/cultural norms from established TW community leaders. In addition to shared cultural practices, participants described greater trust and social cohesion with TW from similar geographic areas.

Conclusion Geographic migration highlights the weight of cultural context in informing network structures and defining influences and leadership in TW communities. Efforts to improve TW engagement in HIV prevention will need to better understand how existing social networks influence HIV risk and prevention and how these can be used to address distinct needs of the heterogeneous Peruvian TW population.