Primary objective: The aim of this study was to explore physical activity (PA) amongst children and young people with Down syndrome (DS). Method and procedures: The youth physical activity promotion model (YPAP) was used to inform semi-structured interviews to explore PA of children and young people with DS. Participants were three males and five females, aged between 6 and 21 years (16.38 + 5.04 years (mean + SD)) who had been diagnosed with the condition DS. Dyadic interviews were conducted with the participant and their parent(s). The interviews were recorded and transcribed, and inductive and deductive analyses of the data were completed. Main outcomes and results: The results were structured around the YPAP Model’s key themes included: enabling factors (seasonal variation, transport, type of activity and independence); predisposing factors (enjoyment, social interaction, dislikes of PA, following instructions, and understanding of PA); reinforcing factors (support and opportunities, parents, and care providers); and barriers to PA engagement (ear problems). Conclusion: The children and young people with DS in the study typically only engaged in fun, unstructured activities. Key facilitators for PA participation were social interactions and parental support. Increasing the level of independence for people with DS within adolescence may have beneficial effects for PA participation in later life.