To explore nursing students' lived experience of a clinical placement within healthcare in a prison, to gain an insight into the support provided prior to and during this unique clinical placement. An inductive phenomenological study. Participants included 14 nursing students from three undergraduate nursing programmes in England, Adult (n = 4), Learning Disability (n = 3) and Mental Health (n = 7). Following a clinical placement in a prison, each participant completed a semistructured audio-recorded interview on MS Teams between October and December 2021. Audio recordings were transcribed verbatim and thematic analysis was completed. Two overarching themes were identified, 'shock' due to the (a) reality of prison; (b) overwhelming emotional impact and (c) frequency and severity of self-harm and 'surprise' due to (a) the need to work with prison officers; (b) recognizing and addressing preconceptions of people in prison and (c) the development of clinical knowledge, skills and becoming a nurse. The need remains for a comprehensive strategy of preparation and orientation for nursing students before commencing a clinical placement in prison, which includes the development of knowledge and clinical skills to support the complex health and social care needs of people in prison. Our research identified the support provided to nursing students prior to clinical placement in prison varies considerably. The development of a preparation and orientation programme has the potential to reduce pre-placement anxiety, emotional burden and support nursing students in addressing their preconceptions of people in prison. This approach is essential to support future nursing students to embrace the unique opportunity of a clinical placement within a prison, enhance their clinical knowledge and skills, and develop as a nurse. Our paper adheres to the consolidated criteria for reporting qualitative research (COREQ). None.