The purpose of this study was to determine the effectiveness of a planned mastery motivational physical play session on physical activity (i.e., heart rate [HR] and physical play intensity [PAHR > 50]) in toddlers (N = 21), as compared to a nonplanned free play session. Participants wore a monitor to measure HR over two, 30 min play conditions. A multivariate analysis of variance was conducted to evaluate the effect of the play conditions. A significant difference between conditions and physiological measures revealed that the mastery motivational physical play session resulted in higher HR and PAHR > 50 when compared to free play. These findings suggest the mastery motivational session resulted in more vigorous physical play in toddlers than free play.