The number of schools for children aged between 4 and 36 months has increased greatly in Spain over the last 20 years, and with that children’s experiences have also changed. The aim of this research is to examine child culture and the factors influencing the relationships that children establish with peers in formal spaces with specific characteristics. According to the results, seniority and playing style influence friendship preferences, along with organisational factors such as the type and number of toys and age structure. This ethnographic research was conducted in the city of Barcelona.