The purpose of the study is to investigate the effect of different environmental conditions on the physical activity of preschool children. The experiment took place in Estonian childcare centre during the free playtime. Fifteen children aged 6–7 years from childcare centre participated in the research. Physical activity was measured using pedometers Fitbit Zip™. Results show that in comparison to the usual free play the physical activity of children increased statistically significantly by 83% when background music was played, by 50% when sport equipment was provided and by 101% when both environmental conditions were combined. It was found that compared to the usual free play, children’s activity increased the least when only sport equipment was provided, while children’s activity increased more when background music was played and increased the most when music with sport equipment was combined. Physical activity did not differ when only background music and music with sport equipment were used. It can be summarised that the background music and opportunity to use portable sport equipment increases the physical activity of children during free play. Background music has greater impact on the activity than portable sport equipment. Children’s physical activity can be effectively increased in childcare centre by using simple modifications such as background music and portable sport equipment during free play.