Internet has become increasingly common in adolescents' daily lives and also in health care. However, there is still need to explore how nurses perceive its use as a part of adolescents' treatment. This explorative qualitative study aim was to explore how nurses perceive the usefulness of Internet in adolescents' outpatient care in mental health. The data were collected among nurses (n = 12) working in two psychiatric adolescent outpatient clinics in university central hospitals in Finland. The data were collected in focus group interviews and analysed using inductive content analysis. The analysis showed that Internet use could promote the care process of adolescents with depression by supporting their self‐reflection and self‐management, enhancing nurses' understanding of adolescents' daily lives and facilitating nurse–adolescent interaction. Disadvantages identified among nurses were fear of role changes in the nurse–adolescent interaction, changes in the intervention, when Internet might be a third party in the face‐to‐face interaction and negative effects of Internet on adolescents. Facilitators in the use of Internet were nurses' positive attitude to Internet, knowledge and experiences of Internet usage. Nurses' negative attitude to Internet and lack of training and instructions were seen as barriers in promoting the successful utilization of Internet among adolescents with depression in outpatient care.