Objective: The purpose of this study was to investigate Japanese undergraduate students' learning experiences as part of an online sexuality education workshop. Design: We employed a qualitative design using in-depth, semi-structured interviews. Setting: The study was conducted at a public university in the Kanto region of Japan. Method: Interviews elicited seven Japanese undergraduate students' perspectives concerning the format of the online sexuality education course and beliefs about sexual health and behaviours. Interviews were analysed using the constant comparative method. Results: Three themes were identifiable in informants' responses: (1) benefits of the online education format, (2) importance of sexuality education for students who live alone and (3) learning about abortion. Students' learning experiences were influenced and shaped by online communication through the sharing of knowledge regarding sexuality, sexual security and sexual health. Conclusion: Although learning took place in a 1-day workshop, there were significant benefits to offering an online sexuality education workshop to Japanese undergraduate students.