Professional identities are important in defining workers' roles, and are concerned with attributes relating to those roles and how they are performed. Evidence shows mental health nurses undertake many different roles as part of their work. Yet, the roles of mental health nurses are insufficiently understood by healthcare staff, service users, and nurses themselves. Mental health nursing work has been deemed invisible and lacking in role clarity. Poor understandings about professional identity of mental health nurses result in difficulties recruiting to the profession, nurses lacking confidence articulating the value of their work, with misunderstandings apparent with service users about the specific role of mental health nursing in their care. The primary focus of this study, conducted in Wales, United Kingdom, was to examine how talk about mental health nursing was handled by participants from multiple perspectives. Data consisted of 17 individual interview transcripts with mental health nurses and 13 interview transcripts from mental health service users, and three focus groups with nursing students. Participants' talk was analysed using thematic analysis. This paper reports how participants described mental health nursing work to have significant role overlap with other multidisciplinary team members. Participants highlighted that mental health nurses often have an ‘in the middle’ label because the complexity of their work can be hard to describe. The implications are pertinent for nurses because if they are considered to be in a liminal position, they risk being perceived as neither one role nor another, resulting in nurses struggling with professional identities and role confidence.