Background: Registration as a children's nurse in Ireland occurs via two routes, an undergraduate degree in children's and general nursing and a twelve-month post-registration children's nurse programme. Candidates undertaking the latter are experienced nurses on the register for either general, intellectual disability or mental health nursing yet they are required to become a nursing student for the duration of the programme. Although anecdotal evidence indicates that this presents unique challenges for these students the experiences of transitioning from registered nurse to nursing student has not been explored since inception of the programme in 2006. Objectives: The study aimed to explore the experiences of the registered nurse that transitioned to nursing student during the Post-registration Children's Nurse Programme, to identify the previous experience of the registered nurse and to identify what challenged and supported successful transition. Design: A qualitative descriptive research design was used. Setting: The study was carried out in a large teaching children's hospital in Dublin, Ireland. Participants: A purposeful sample of six registered nurses that completed the programme within the last 12 months was interviewed about their experiences of being a post-registration nursing student. Methods: Face-to-face, semi-structured, conversation-style interviews were conducted. Results: Four main themes were identified from the data: ‘Feelings related to returning to student status’, ‘Supports throughout the transition’, ‘Differences between disciplines’ and ‘Knowing  your place’. Registered General Nurses (RGN) had different learning needs in comparison to registered nurses in intellectual disability (RNID) and expressed difficulty adapting to the role of nursing student as they felt that their previous knowledge and experience was being overlooked. In contrast, RNIDs were more challenged on clinical placement by unfamiliarity with clinical equipment and terminology. Both RNIDs and RGNs found that the nursing staff on their placements were a source of support despite reporting that they rarely worked with their designated preceptor. Conclusions: The challenges experienced by nursing students from different nursing disciplines sharing the same post-registration programme needs to be considered in the planning and implementation of all aspects of the programme. Healthcare staff should become more aware of the challenges experienced by the postgraduate nursing student when educating and supporting their learning within the preceptor-student relationship.