Social influence has a prominent role in theories on fertility, implying that people’s reproductive decision-making is affected by the choices and behaviours of others. Multiple social influence mechanisms are thought to change people’s fertility behaviour, including social learning, social contagion, social capital, and social pressure. Comprehensively investigating these mechanisms of social influence in contemporary populations has been difficult, and most findings stem from convenience samples, qualitative studies, or studies focussing on single mechanisms. Here we examine the opportunity for social influence by these different mechanisms simultaneously using a unique representative sample of 706 Dutch women reporting on 17,650 social relations (obtained via the LISS panel). In particular, we investigated variation in the composition of the network in terms of fertility-relevant characteristics, including the number of childfree individuals in the personal network, the number of people with (young) children, and the number of people that can help you with child care. Characterising variation in these traits in personal networks gives unique insights into the opportunities for social influence. Follow-up studies will address how such variation shapes fertility behaviour.