AimThis study explored nursing students' eHealth literacy, lifestyle behaviours and COVID‐19‐related preventive behaviours and associated factors.DesignA cross‐sectional comparative correlational study.MethodsNursing 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.ResultsCOVID‐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).ConclusionsFindings 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.