This study investigates differences in physical activity levels and patterns by participation in sport and day among early and mid-adolescent Spanish girls (N = 177, aged 11-16 years) who responded to a Spanish adaptation of the Four-by-One-Day Recall Physical Activity Questionnaire. The results indicate that the girls spent most of their time engaged in light and very light activity and spent limited amounts of time on moderate and vigorous activity on weekdays and weekends. Moderate and vigorous activity declined from early to mid-adolescence and participation in sport did not appear to prevent a decline in overall physical activity. Educational programmes promoting a more active lifestyle should target young people who are less physically active, while preventing the general decline in physical activity.