The Social Identity Approach to Health holds that groups provide us with a sense of meaning and belonging, and that these identity processes have a significant positive impact on our health and wellbeing. Typically, research drawing from the social identity approach with adolescents has focused on the benefits of existing group memberships. Here, using a sail-training intervention, we investigated the impact of providing adolescents with a new group (i.e., a new social identity) on psychological resilience. Across two studies, we demonstrate the benefits of a new social identity, in terms of increases in psychological resilience, flow predominantly to those adolescents who report the lowest levels of resilience at the start of the voyage. We discuss our findings in relation to the social identity approach and adolescent identity development more generally.