How new members are integrated into a particular group environment—also known as organizational socialization processes—have been shown to be a powerful predictor of newcomer adjustment in the workplace. Yet, there is a scarcity of research on how sport teams manage the integration of new team members, and the consequences of different tactics. The current research evaluated how socialization processes are associated with youth athletes’ perceptions of their group environment. Across two time points, 202 competitive adolescent ice hockey players from 15 teams (Mage = 14.47, SD = 1.22, 54 females) completed measures of team socialization processes, social identity strength, and cohesion. Athletes’ perceptions of team socialization processes (T1) were positively associated with social identity (T1 and T2) and cohesion (T1 and T2). Mediation analyses revealed that coach-initiated role communication tactics were positively associated with social identity change that, in turn, corresponded to higher levels of social and task cohesion. The results suggest that the processes surrounding the integration of new members may be a key lever for managing the social environment for athletes in youth sport.