ABSTRACT Objective Growing evidence shows that online mental health interventions for university students are a cost-effective means for addressing mental health problems among university students. This study presents data on the numbers and characteristics of students who engaged in an online mental health promotion intervention called YOLO in the context of a university-wide rollout of the program before and after the onset of the COVID-19 pandemic. Methods Participants completed a questionnaire assessing socio-demographics and mental health (wellbeing and distress). A total of 240 students accessed the program over a 12-month period and of these, 164 provided reliable data. Results YOLO was accessed by students representing diverse socio-demographics including domestic vs. international student status, degree level, faculty, ethnicity, and age, although there was an over-representation of females (77.2%). Students who accessed YOLO pre-COVID-19 did not substantially differ across most mental health dimensions from those who accessed it during-COVID-19, although more students reported mild-moderate anxiety symptoms during-COVID than pre-COVID-19. The only socio-demographics significantly associated with mental health were age and degree level. Younger age was related to higher anxiety and 3rd and 4th year undergraduate students reported poorer mental health comparative to students in other years. Additionally, a higher proportion of these students accessed YOLO during-COVID-19 than at pre-COVID-19. Conclusion The present data along with findings from other studies that have evaluated YOLO, suggest that online mental health promotion programs that do not require in-person contact are an important and necessary resource for all university students.