Purpose: This study examined the relationship between adolescents (N = 124) from physical education classes keeping a daily online leisure-time physical activity (LTPA) record and feelings of competence toward LTPA, motivational profiles toward LTPA, and LTPA behaviors. Method: A repeated measures ANCOVA was used to examine the relationships between recording compliance and perceived competence, motivation, and physical activity. Results: As students kept the LTPA record, boys' LTPA levels significantly increased and girls' levels significantly decreased. A significant interaction between recording compliance and introjected regulation was found; the more students recorded the less motivated they were by guilt or obligation to exercise. A significant interaction was found between recording compliance and intrinsic regulation, showing the more students recorded the more intrinsically motivated they were to exercise in their leisure time. Discussion/Conclusion: Implications and suggestions are described for physical education professionals.