This paper examines the evolution of student volunteers’ motivation during their participation in a sports-based outreach project and how their experiences during the programme serve to influence their commitment and retention to it. The Sport Universities North East England (SUNEE) project is a university-led community outreach initiative that provides the region's student volunteers with vast opportunities to gain both experience and qualifications as sports coaches, mentors and leaders by working with a range of hard-to-reach groups. This work draws on qualitative data generated from semi-structured interviews (n = 40) and describes a sequence of motivational transitions undergone by student volunteers over the course of their involvement in the project. In order to illustrate this, the paper applies the socio-psychological framework of Self-Determination Theory (SDT) to not only index the type of motivations that compel students to volunteer on the SUNEE project, but to also track motivational adaptation and reveal the features occurring within the project, which serve to either facilitate volunteer motivation or retention (Deci & Ryan, 1985, 2000). By using the example of the SUNEE project, this research demonstrates how students’ motivation to volunteer changes from the extrinsic (i.e., instrumental reasons such as enhancing one's employability profile) to the intrinsic (i.e., enjoying the experience) motivations the longer the person has taken part in the project. The findings demonstrate the utility of the SDT as a framework with which to understand student motivation to volunteer within a university-led sports-based community outreach setting. The theoretical contributions of the study to the literature on student volunteering are outlined, and implications are drawn for practice and future research.