Pre-exposure prophylaxis (PrEP) has limited availability across Latin America, though access is increasing. We explored PrEP uptake in Mexico via an online survey completed by Spanish-speaking, Hornet geosocial networking application (GSN app) users without HIV (n = 2020). Most (81.3%) had heard of PrEP, 3.5% were current users, and 34.2% intended to take PrEP within six months. Current PrEP use was associated with PrEP eligibility (aOR 26.07 [95%CI 13.05–52.09], p < 0.001), recent STI testing (aOR 3.79 [95%CI 1.10–13.11], p = 0.035), and recent chemsex (aOR 3.02 [95%CI 1.02–8.93], p = 0.046). Recent STI testing was associated with hearing about PrEP from a doctor (aOR 3.26 [95%CI 1.98–5.36], p < 0.001), and those who lived in large cities were less likely to have learned about PrEP via Hornet (aOR 0.52 [95%CI 0.32–0.85], p = 0.009). Interventions to increase PrEP uptake in Mexico should build upon existing health networks and utilize GSN apps for PrEP information dissemination, particularly in less populated areas.