The aim of this study was to establish whether various types of play equipment differentially constrain exploratory behavior and spontaneous physical activity patterns in preschoolers when they play freely with them. Fourteen children, 3-4 years old, played with four different types of equipment. The children wore an accelerometer and data were analyzed taking into account overall physical activity, the time spent at different intensity levels of move-ment, and the entropy of the time series. All trials were video-recorded and a systematic observation instrument was used to register actions and interactions with partners and equipment. The data were subsequently analyzed by means of principal component analysis (PCA) and the dynamic overlap order parameter, to identify the rate and breadth of exploratory behavior on different time scales. Our results revealed that the children were physically less active when playing with portable and small equipment. The PCA showed that when playing without equipment, the children usually played standardized games, like playing tag, in groups. Movement patterns were more or less varied depending on the equip-ment, and thus some equipment constrained the emergence of different types of games or motor behavior.