It appears to be a challenge to keep young adolescents involved in sports, while motivation has been confirmed as a key determinant for sport participation. Consequently, the aim of this study was to get a better insight into the motivational aspects and barriers of young adolescents while paying attention to the various contexts of youth sports in the Netherlands (i.e., club, commercial and urban sports). In total, 741 young adolescents (ages 12–15) filled in a questionnaire about the motivation and barriers to participate in sports and starting a new sport. The most important motivational factor in all sports contexts appears to be ‘fun/pleasure’. Additionally, they like the atmosphere of sports, and are motivated by learning new skills and becoming better at sports. Furthermore, young adolescents value a positive atmosphere, a skilled trainer and being able to participate at their own level (with others) when starting a new sport. Identified barriers are ‘liking other activities’, ‘a lack of time’, and that ‘sport is not fun anymore’. Nevertheless, the young adolescents surveyed, even those not active in sports, generally do not experience a high degree of barriers to participate in sports. The findings provide directions for developing future interventions that improve sport participation and prevent dropout.