Physical activity (PA) has numerous health benefits for children using wheelchairs. Therefore, this qualitative study aimed to get a comprehensive overview of their PA behaviour and its determinants. Seven boys and five girls aged 7–11 years participated in semi-structured interviews, exploring type, duration, setting and intensity of weekly PA. Using a qualitative content analysis determinants and participants’ PA were identified and categorized into organized and unorganized settings based on a socioecological model (SEM). Main Barriers included inadequate physical environments, acceptance from peers and insufficient competence of teachers and coaches. Public places and schools need to be more accessible and should increase offers of inclusive sports programmes. The study provides novel insights into PA patterns and influencing factors and highlights the need for more supportive and inclusive environments. Future research should further explore therapy as an additional source of PA.