The developmental processes of identity exploration and formation in adolescence often take place within the context of leisure activities. The discovery model of identity formation proposes that these processes are reflected in part by adolescents' subjective identity-related experiences including personal expressiveness, flow, and goal-directed behaviour (Waterman, 1990, 1993). This model, however, has not been tested with cross-national samples. The purpose of this study was to examine the applicability of this general model of identity-related experiences within self-defining activities for a sample of 493 adolescents from the United States, Chile, and Italy. Confirmatory analyses of a three-factor model showed strong invariance across countries. Findings indicated that most adolescents reported high levels of identity experiences within self-defining activities. Results from Multivariate Analyses of Variance indicated considerable commonalities and a few significant differences in these experiences across the three countries and across five broad activity classes. Findings are discussed in the context of the growing literature on adolescent activity involvement and the relation of activities to identity exploration.