Abstract: Many young people in the Netherlands participate in voluntary sports clubs (VSCs) but stop once they become adults. VSCs lack the ability to transition their youth members to adult members, which threatens the size of the clubs in terms of membership, the income, and the availability of volunteers. This research aims to identify experiences of young adult members that contribute to membership involvement (MI) and intentions to support the club and continue membership (membership commitment). A mixed-method approach consisting of a qualitative and a quantitative study was used. The results showed that young adult members elaborate on a wide range of experiences that predicts MI at four stages of membership. These experiences can be classified into the pleasure when participating in sports (enjoyment), the service and support within the club (care), and the social connectedness among the members (closeness). Moreover, the results revealed that MI performs as a mediator for membership commitment. The conclusion indicates that experiences of young adult members are integrated system, one cannot do without the other. This integrative system of experiences determines membership involvement in all stages of membership, from less than one year to long-term memberships. For clubs it is important to address these experiences because MI is important for the development of membership commitment - loyal and supportive young adult members.