PURPOSE: Participation in physical activity (PA) is reported to decline in adolescence, particularly for girls. However, we do not know if this decline in PA is consistent across modes and settings or whether there are transfers of participation between modes and settings. Nor do we understand the changes in specific types of PA or the interaction between types of participation and different modes/settings. This study investigated contexts of PA participation for female adolescents at two life transition points. METHOD: A survey of 489 Year 7 and 243 Year 11 adolescent girls was conducted, incorporating a measure of overall PA level and participation rates in seven modes/settings and in specific types of sport and PA. RESULTS: Less than half of the respondents met or exceeded the recommended level of moderate or vigorous PA--60 min or more--on the previous day, and there was no statistically significant difference in the proportions in Years 7 and 11 (39.5% vs. 45.9%; p > .05). However, older adolescents shifted their participation away from organized, competitive modes and settings toward nonorganized and noncompetitive modes and settings and individual types of PA. CONCLUSIONS: An understanding of the changes in PA modes and settings identified here can inform the planning of policies and implementation of programs for the promotion of PA by adolescent girls.