Aim: This study explored nursing students' eHealth literacy, lifestyle behaviours and COVID-19-related preventive behaviours and associated factors. Design: A cross-sectional comparative correlational study. Methods: Nursing students (n = 358) from a metropolitan area of South Korea were recruited for an online survey. The online questionnaire included: The eHealth Literacy Scale, the Health Promoting Lifestyle Profile-II and the COVID-19-related preventive behaviour scale. Results: COVID-19-related preventive behaviours correlated positively with satisfaction with one's major, time spent seeking health information online, eHealth literacy and lifestyle behaviours. Significant factors affecting COVID-19-related preventive behaviours were the following: being female (β = 0.194, p <.001), time spent seeking health information online (β = 0.114, p =.002), eHealth literacy (β = 0.167, p =.001) and lifestyle behaviours (β = 0.266, p <.001). Conclusions: Findings highlight the need to strengthen searching behaviours to access accurate health information online and reinforce eHealth literacy and health-promoting lifestyle behaviours to improve COVID-19 preventive behaviours among nursing students.