INTRODUCTION: We examined the association of pre-exposure prophylaxis (PrEP) programme retention with the use of daily, event-driven (ED) or regimen switching reported during follow-up at any point prior to discontinuation among men who have sex with men (MSM) in Hanoi, Vietnam. METHODS: Between April 2020 and February 2023, we collected data from PrEP clients at Hanoi Medical University Sexual Health Promotion clinic who were prescribed either ED or daily PrEP at the initial visit; at subsequent visits, clients reported the regimen used since the prior visit. We defined three categories of PrEP use: ED-PrEP exclusively, daily PrEP exclusively and switching regimens. The primary outcome was time to discontinuation in the PrEP programme during the study period, defined as missing a scheduled visit by > 30 days. We performed survival analysis using Kaplan-Meier curves. RESULTS: In total, 2107 people were included: 61.1% (n = 1288) reported exclusive use of daily PrEP, 10.4% (n = 220) reported exclusive use of ED-PrEP and 28.4% (n = 599) reported switching PrEP regimens. Among switchers, 29.40% (n = 176) switched more than once. Furthermore, 82.5% switched from daily to ED-PrEP and 17.5% switched from ED to daily PrEP. The median time to discontinuation in the PrEP programme was 105 days (IQR: 52-182) among those reporting exclusive use of ED-PrEP, 104 days (IQR: 56-274) among those reporting exclusive use of daily PrEP and 163 days (IQR: 101-308) among those who switched. Among switchers, those who switched more than once had a median time to discontinuation in the PrEP programme of 231 days (IQR: 137-380) in comparison to 133 days (IQR: 90-274) for those who switched once. CONCLUSIONS: We provide real-world data from MSM in an HIV PrEP programme in Vietnam that those who switched had longer periods of retention during the study period. Our findings suggest that offering flexible PrEP regimen options may improve engagement and long-term adherence among this population.