Outdoor time is a positive correlate of physical activity in preschoolers; however, children remain highly sedentary even outdoors. This cross-sectional study thus aimed (1) to measure the physical activity levels of 30 preschool-aged children attending a centre-based childcare centre in a remote region located in Northwestern Québec (Canada) and (2) to identify the factors associated with moderate-to-vigorous physical activity (MVPA) during outdoor time. Two observers monitored the children individually over a period totalling approximately 40 h using a translated version of the "Observational System for Recording Physical Activity in Children--Preschool version" (OSRAC-P). In addition, parents and early childhood educators each completed a short questionnaire to, respectively, collect child demographics and educators' personal characteristics and physical activity habits. When children were outdoors, sedentary activities predominated (60.2%), compared with light activities (18.1%) and MVPA (21.7%). A binary logistic regression analysis also showed that MVPA was associated with different social and non-social factors: the group composition, the early childhood educator, the prompting behaviors, the outdoor educational context, the time of day, and the children's age and sex. Although no clear profile of early childhood educators seemed to be linked to children's MVPA, some factors under their control appear to contribute to increasing preschoolers' PA. Prompting children to be active and integrating more high energy expenditure activities in their daily routine stood out as good ways to optimize time spent outdoors.