Abstract Natural outdoor environments provide important settings for children to engage in physical activity. It is unclear if these relationships also exist in preschool aged children. We examined associations between amount and type of neighbourhood vegetation and blue space, proximity to the beach and preschooler's device‐measured movement behaviours. Accelerometer data from 1081 preschool children were processed into physical activity and sedentary behaviours using a machine learned random forest physical activity classification model specifically developed for children under five. High‐resolution aerial imagery data and Geographic Information Systems were used to identify total percentage of neighbourhood vegetation and vegetation components (grass, shrubs and trees) and presence and total percentage of blue space (ocean, riverways and lakes and swamps) for 500, 1600 and 5000 m service areas around children's residences. Distance to the closest beach, patrolled beach, and dog beach were also calculated. Amount of neighbourhood vegetation was inversely associated with boys sedentary time in the 500 m (β = −0.91 min/day, p = 0.006, 95% CI [−1.55, −0.33]) and 1600 m (β = −1.30 min/day, p = 0.001, 95% CI [−2.08, −0.53]) service area, and positively associated with walking time in the 1600 m (β = 0.12 min/day, p = 0.045, 95% CI [0.02, 0.22]) service area. The presence of local riverways was positively associated with girls walking time in the 1600 m (β = 2.34 min/day, p = 0.009, 95% CI [0.59, 4.09]), and 5000 m (β = 1.67 min/day, p = 0.019, 95% CI [0.27, 3.06]) buffer. Distance to dog beach was positively associated with boys sedentary behaviours. Presence of lake and swamps were negatively associated with boys walking, and presence of riverways was negatively associated with girls moderate‐to‐vigorous activities and games and boys running in the 5000 m service area. These findings suggest higher amounts of neighbourhood vegetation and certain types of blue space such as riverways and dog beaches could facilitate positive movement behaviours in young children. Our findings that natural outdoor environments are associated with preschool children's movement behaviours add to evidence which could contribute to policy implications for urban planning and the provision and protection of natural environments within cities. Read the free Plain Language Summary for this article on the Journal blog.