OBJECTIVE: To explore the frequency of and reasons for using condoms among men who have sex with men (MSM) on preexposure prophylaxis (PrEP). DESIGN: We analyzed quantitative app-based diary data on daily sexual practices (August 2015-February 2019) and qualitative in-depth interviews among MSM using daily PrEP and event-driven PrEP (edPrEP) in the Amsterdam PrEP demonstration project. METHODS: Participants could report daily about sex acts, PrEP use and condom use per partner type (steady and casual partners). We examined four strategies of PrEP and condom use: PrEP only, PrEP and condoms, condoms only, and neither strategy. We compared the proportions of sex acts per strategy between PrEP regimens. In 43 in-depth interviews, we explored motives for implementing each strategy. RESULTS: Three hundred and fifty-two participants reported 48 949 anal sex acts. PrEP only was the most common strategy employed with any partner type (81%, n = 39 650/48 949) and was motivated by anticipating more pleasurable sex, sexually transmitted infection's perceived curability, and habituation to condomless sex. Combining PrEP and condoms was more often chosen for sex acts with casual partners (18%, n = 6829/37 317) than with steady partners (5%, n = 614/11 632) and was linked to, for example, higher perceived vulnerability for sexually transmitted infections or HIV and avoidance of PrEP disclosure. Condoms only was uncommon but occurred particularly among edPrEP users (4%, n = 379/8695). Applying neither strategy was common among edPrEP users with steady partners (25%, n = 538/2122) and was motivated by low perceived HIV risk. CONCLUSION: Condoms remain a viable option for PrEP users in certain settings. Condoms were applied in higher risk settings, to avoid PrEP disclosure, or as substitute for PrEP, especially among edPrEP users.