This article examines the data obtained through a year-long ethnographic study of students from a Spanish primary school, and sheds light on their use of gender code networks during school recess. The results of this analysis confirm the conclusions on student interaction drawn by other studies (group segregation regarding age and gender and, accordingly, the practice of different activities, the occupation of different spaces; ways of inclusion or exclusion, and the safeguarding of codes). The use of codes is random, the rules which regulate peer interaction are diffuse, and the code network becomes extremely complex. In spite of this, this study concludes that a new student learns to interpret and use the codes in a short period of time (six weeks maximum, according to the cases analyzed) even when the student is not a native speaker of Spanish and is unable to understand the language. We also observed in the case of all newcomers, an initial "period of openness" during which they try to suspend their own codes and open up to learning the codes present in their new context.