Objective: Studies indicate that those participating in sports are a high-risk population for hazardous alcohol use. Previous research identifies psychosocial drivers underpinning this link between sports participation and risky drinking behavior; however, the evidence is restricted to cross-sectional prevalence studies. Theoretical evaluations suggest that psychologically constructed identities are a defining factor for behaviors in this context. Therefore, the present study sought to examine longitudinally the relationships among sports-related identities, well-being, and alcohol behaviors in those participating in sports. Method: Respondents completed self-report questionnaires on their alcohol consumption, drinking motives, athlete identity (personal identity), sports group identification (social identity), and general well-being. A sample of 475 participants (male = 55.6%; mean age = 20.2 years) provided data at Time 1 for cross-sectional analysis. Longitudinal associations were conducted with 92 participants (male = 42.4%; mean age = 20.8 years) who provided follow-up data (Time 1 and 6 months later). Results: Cross-sectional results revealed an association between social identity and alcohol consumption, which was fully mediated by positive reinforcement drinking motives. Correlation analysis found a significant positive relationship between Time 1 alcohol consumption and social identity 6 months later. Furthermore, social identity was positively associated with consumption, whereas athlete identity was negatively associated therewith. Finally, well-being was positively associated only with sports group identification over time. Conclusions: Our findings suggest that sport-related drinking may be an avenue for building group identification, and this identification is linked to well-being.