International students transitioning to university undergo dramatic changes in social identity, with a need to adapt to a new culture, language, environment, and way of living. This paper explores the impact of this social identity change on academic performance, academic retention, mental health, and life satisfaction. The Social Identity Model of Identity Change (SIMIC) predicts that during life transitions of this form, an individual’s group memberships and associated social identities can protect them from the negative effects of life change. This longitudinal study tested SIMIC among international students (N = 210) transitioning to study overseas, with data collected at three time points across a Foundation Year programme in a large Australian university. Consistent with SIMIC, continuity of social identities predicted higher academic performance and better life satisfaction, and indirectly predicted student retention over time.