Introduction and background: Nursing shortages have resulted in an increased interest in work-based learning programmes supporting employed healthcare assistants (HCAs) to train simultaneously as student nurses. This requires them to fulfil concurrent roles of both HCA and student. Successful transition generally results from exiting one role and accepting another, therefore these HCA/students risk remaining in a no-mans-land between the two roles. This study explored the practice experiences of one cohort of students and mentors in relation to the students’ dual roles. Methodology: The research was carried out using an exploratory sequential mixed methods approach, with a thematic literature review, qualitative interviews and a quantitative pilot evaluation of one intervention arising from the qualitative phase. Findings: The dual roles of HCA and student nurse created a potential barrier to students’ professional socialisation. Their ability to transition to the student nurse role was impacted by the primacy of the HCA role, lack of role clarity and the perceptions of other team members which resulted in them being perceived as ‘HCAs doing extra’ rather than as student nurses. However, visual reinforcement, through artefacts such as uniform and by avoiding placing the students in their employed areas, was perceived as beneficial. Mentors did not identify such role duality issues for themselves. The introduction of a booklet was intended to reinforce the student role when appropriately applied. Conclusions: This exploratory sequential mixed methods research supported the development of new knowledge through identification of the experiences of this student cohort. New theory was derived from the development of a revised professional socialisation transition process for this group of students, but further research is needed to identify the generalisability of this theory. Whilst the pilot evaluation of the booklet was impeded by a poor response rate, service colleagues still believe this to be beneficial and have continued to use it in practice. Further work is needed to embed the booklet in practice and further explore its efficacy.