This chapter maps the spatial structure and composition of the social world of children aged three months to three years. Drawing primarily on video-based spot observations of 45 children, it first examines the number of social partners present in body contact, within arm’s reach, and within sight. The findings show that infants and toddlers are typically engaged in multiple relationships, rarely in dyadic contexts and hardly ever alone. The chapter then differentiates children’s social worlds by kinship, gender, and age categories. It reveals that mothers, preadolescent childminders, and peers play prominent roles, though in varying ways across different stages of early childhood. While mothers are almost constantly present during the first months, their time with children decreases rapidly as the children grow older. Peers are present from the beginning but become the most frequent social partners once children start walking, surpassing all other categories combined. Preadolescent caregivers are most involved in the second half of the first year, a period when infants require less intensive care but are not yet mobile. Although multiple or distributed caregiving has been widely documented across societies, the chapter argues that the role of peers in the earliest years has rarely been examined in detail and warrants greater attention.