Rehabilitation research investigating activity participation has been largely conducted in a realist tradition that under‐theorises the relationship between persons, technologies, and socio‐material places. In this Canadian study we used a post‐critical approach to explore activity/setting participation with 19 young people aged 14 to 23 years with complex communication and/or mobility impairments. Methods included integrated photo‐elicitation, interviews, and participant observations of community‐based activities. We present our results using the conceptual lens of assemblages to surface how different combinations of bodies, social meanings, and technologies enabled or constrained particular activities. Assemblages were analysed in terms of how they organised what was possible and practical for participants and their families in different contexts. The results illuminate how young people negotiated activity needs and desires in particular ‘spacings’ each with its own material, temporal, and social constraints and affordances. The focus on assemblages provides a dynamic analysis of how dis/abilities are enacted in and across geotemporal spaces, and avoids a reductive focus on evaluating the accessibility of static environmental features. In doing so the study reveals possible ‘lines of flight’ for healthcare, rehabilitation, and social care practices.