Long-acting injectable PrEP could offer an alternative to daily oral PrEP, improve adherence and protection, if found acceptable, safe and effective. HPTN 077 evaluated injectable cabotegravir safety, tolerability and pharmacokinetics among HIV-uninfected males and females in sequentially-enrolled cohorts of two dosing strategies. We compared acceptability of product attributes, prevention preferences and future interest in injectable PrEP (FIIP) by region, sex-at-birth, arm and cohort and used multivariable analysis to identify FIIP determinants. Baseline injectable PrEP preferences were higher in non-U.S. sites and increased in both regions over time. In multivariable models, FIIP was most strongly associated with acceptability of product attributes, was higher in non-U.S. sites and more altruistic participants. Treatment arm and report of pain were not associated with FIIP. Injectable acceptability was highest in non-U.S. sites. Preferences for injectable versus other PrEP methods were higher among U.S. males than females, but higher among males and females in non-U.S. settings.