This study aimed to: (a) compare the physical activity (PA) levels (i.e., moderate-to-vigorous PA [MVPA] and total PA [TPA]) of preschoolers in 3 different early-learning environments (center-based childcare, home-based childcare, and full-day kindergarten [FDK]); and (b) assess which characteristics (e.g., play equipment, policies, etc.) of these settings influenced preschoolers' PA. Method: Twenty-seven facilities (9 centers, 10 homes, and 8 FDK) participated in this study. Participants (aged 2.5-5 years; n = 297) were fitted with Acticale[TM] accelerometers for 5 consecutive days during childcare/school hours to assess their PA. The Environment and Policy Assessment and Observation (EPAO) tool was used to objectively examine the PA environment of all participating facilities. Finally, demographic questionnaires were administered to preschoolers' parents/guardians. Results: Preschoolers in FDK accumulated significantly more MVPA (p