Objective: This study explored factors affecting the implementation of good-quality physical activity provision in after-school childcare delivered in a Canadian jurisdiction without specific policy, standards or active interventions aimed at increasing physical activity underway. Design: Case study design theoretically guided by the implementation literature. Method: Of the 80 childcare centres in Victoria, British Columbia, Canada, 50 were eligible or available to participate. Managers from centres who agreed to participate responded to direct recruitment (n = 9); an additional seven staff were recruited through snowball sampling (n = 7). Semi-structured interviews explored macro-, organisational- and individual-level factors influencing implementation. Coding strategies suggested by grounded theory (open, axial and selective), constant comparison with the literature and an a priori conceptual framework were used to analyse the data. Results: Three primary themes ('Being confined', 'Working together to pull it off' and 'It takes skill') and three subthemes ('It's a moving target', 'We have to make do' and 'Centre rules and routines dictate practice') emerged from the analysis. Conclusion: The study contributes to the understanding of facilitators and barriers to the implementation of good-quality physical activity provision in typical after-school childcare centres. This information can inform guideline and implementation resource development. (author abstract)