Background: Understanding how and where children accumulate their physical activity (PA) and sedentary minutes throughout the day has important implications for behavioral interventions. Purpose: The purpose of this study was to examine the duration and intensity of habitual PA and sedentary time (SED) at and away from school among preadolescent children. Methods: Data from twenty-one children ages 7-11 (57% girls; 57% nonwhite; 24% overweight/obese) were included in this analysis. Proportion of time spent in PA, SED, and SED bouts were examined on school days (in-school and out-of-school) and non-school days via accelerometry. Results: When comparing school time with non-school time on school days, children accumulated a higher proportion of light PA while in-school [49.3% (i.e. 5 min 18 s) vs. 39.6% (i.e. 3 h 53 min), p = 0.01]. While at school, the proportion of time spent in SED was less [46.3% (i.e. 3 h 7 min) vs. 56.3% (i.e. 5 h 32 min), p = 0.01] and fewer children spent time engaged in prolonged sitting compared to out-of-school [uninterrupted SED for 30 min 52.4% (i.e. 11 children) vs. 85.7% (i.e. 18 children), p = 0.02]. Discussion: These findings suggest children are proportionately most active and least sedentary when at school, yet children only accumulated approximately 18 min of moderate-to-vigorous PA in this environment. Translation to Health Education Practice: These preliminary findings can help to inform physical activity programming designed to promote life-long physical activity behaviors in children.