Mothers’ social integration with other mothers in the same residential area has been shown to be beneficial for their health and well-being. The socio-psychological resources afforded by other mothers aid the transition to motherhood. However, much less is known about the processes whereby mothers integrate with other local mothers. Therefore, we analysed first-time mothers’ experiences of social integration with other mothers in the same neighbourhood. Through three waves of semi-structured interviews, we followed eight Finnish first-time mothers’ everyday lives for a year. The narrative analysis of these longitudinal interviews revealed three story types – social integration, social exclusion and social disconnection – that depicted mothers’ different experiences of integration with other local mothers. The perceived similarity of experiences, goals and interests related to motherhood enhanced the development of a shared sense of identity and supported integration with other local mothers. We discuss our findings in relation to the social identity model of identity change (SIMIC).