The purpose of this study is to determine the effect of two physical education (PE) instructional climates (mastery, performance) on the percentage of time students spent in a) moderate-to-vigorous physical activity (MVPA) and b) management tasks during PE in 2nd-grade students. Forty-eight 2nd graders (mastery, n = 23; performance, n = 25) participated in a daily, school-based five-week PE intervention. All students also participated in typical PE during a baseline phase, thereby serving as their own control group. The System for Observing Fitness Instruction Time (SOFIT) was used to describe the lesson context and students' physical activity for each PE session. Students spent an average of 36.9%, 9.9%, and 23.5% of class time in management tasks during typical PE, mastery, and performance climates, respectively. The mastery climate spent significantly less time in management compared to the performance climate and typical PE (p < 0.001). Results indicated that students engaged in significantly more MVPA during the mastery (68%) and performance (67%) climates compared to typical PE (49.7%) across 24 lessons (p < 0.05). Results suggest that a mastery climate can decrease the percentage of time spent in management tasks and that a structured intervention can increase MVPA in 2nd-grade students.