Background Young children depend on adult caregivers to provide opportunities for physical activity. Research has focused on barriers and facilitators to children's physical activity while in childcare, but parental influences remain largely unknown. This study examines parent's attitudes about preschoolers' physical activity and outdoor time, compares them with those of childcare providers and determines the association between parental attitudes and preschoolers' measured activity. Methods Parents and childcare providers from 30 childcare centres were surveyed regarding attitudes towards preschoolers' physical activity and outdoor time. Children's moderate‐to‐vigorous physical activity was determined by using 24‐h accelerometry. Parent and childcare providers' responses were compared. Mixed‐effect linear regression examined moderate‐to‐vigorous physical activity and sedentary time as outcomes with parental attitudes as predictors, family demographics as covariates and centre as a random effect. Results Three hundred eighty‐eight parents and 151 childcare providers participated. On average, children were 4.3 (0.7) years old. Parents and childcare providers both considered daily physical activity important for preschoolers, but providers rated the importance of daily outdoor time higher on a 10‐point scale (8.9 vs. 7.6, P < 0.001). More parents than providers believed that children would get sick by playing outside in the cold (25 vs. 11%, P < 0.05). Parents were more comfortable with their child playing outside at childcare compared with outside at home (8.9 vs. 6.9, P < 0.001). Lower income parents felt less comfortable than higher income parents with their child playing outside either near home or at childcare. Neither home nor total child activity levels were associated with most parental attitudes queried. Conclusions While parents and childcare providers value daily physical activity for children, some parents expressed discomfort about their young children engaging in outdoor play, especially around home and in cold weather. These findings highlight the importance of childcare‐based interventions to promote preschoolers' physical activity and outdoor play.