Objectives Exercise referral schemes (ERSs) are internationally widespread. This study aimed to gain an insight into differential engagement through understanding participant experiences of patients referred by healthcare professionals to one such scheme in the UK. Design The study employed a qualitative longitudinal approach using semistructured interviews, with results reported using Consolidated criteria for Reporting Qualitative research guidelines. Setting Two leisure centres providing an â € emerging best-practice' ERS in northeast England. Participants Referred patients (n=11), who had not yet commenced the scheme, were recruited on a voluntary basis. Seven females and four males, with a range of non-communicable diseases, such as cardiovascular disease, mental health issues, diabetes, overweight/obesity and musculoskeletal problems, participated. Intervention 24-weeks, two times per week, of supervised exercise sessions and three one-to-one assessments (prescheme, 12 weeks and 24 weeks) for patients referred from primary and secondary care. Primary outcome measures Two longitudinal semistructured interviews, prior to commencement and 12-20 weeks later, were thematically analysed using the framework approach. Analysis comprised seven stages: transcription, familiarisation, coding, development and application of an analytical framework, charting data using a matrix and interpretation of data. Interpretation went beyond descriptions of individual cases to develop themes, which identified and offered possible explanations for differing participant experiences. Results Three overarching themes emerged. First, â € success', with engaged participants focused on health outcomes and reported increases in physical activity. Second, â € struggle', with short-term success but concerns regarding continued engagement. Participants reported scheme dependency and cyclical needs. Finally, â € defeat', where ill health, social anxiety and/or poor participation experience made engagement difficult. Conclusion Some success in engaging those with non-communicable diseases was reported, resulting in positive effects on health and well-being. The study highlights complexity within ERSs and inequality of access for those with challenging health and social circumstances. Improved, or different, behaviour change support is required for referrals finding engagement difficult.