The role that social support and social networks play in mediating isolation and stress experienced by vulnerable families is well established. However, a major issue facing supportive human services is to find and engage families with limited social networks and link them to supports that could improve outcomes for their families. This paper reports on the results of in‐depth interviews with 20 sole parents with children aged under 5 who were not well connected to services. It documents their social networks with the use of a social network map. Using a social capital lens, the analysis attempts to differentiate the different relationships in the participants' lives. Most participants were not satisfied with their informal networks, with conflicted or ambivalent reliance on family, absence of support and community engagement and fragility of informal networks. Although this group of isolated mothers does encounter the formal service system, the opportunities to increase and strengthen their networks do not eventuate. Better understanding of the nature and extent of social networks can inform practitioners and policy‐makers of the critical factors needed to increase service use for parents with limited resources.