Despite the age restrictions of social networking sites (SNS) averaging age 13 years, younger children are engaging with these sites (Ofcom, 2019). Research has shown that SNS use exposes the user to many risks, such as cyberbullying and lower self-esteem. Alternatively, SNS use can enhance social capital (maintenance formation of friendships). Current literature has considered these mostly within adolescent and adult samples. This study aims to investigate the extent to which children's behaviours on SNS predict risk and benefit outcomes. Within a sample size of 883, 351 children (aged 7-to-12 years) identified accessing SNS; these children completed an online survey measuring online self-disclosure, self-presentation, digital literacy skills, social capital, experiences of cyberbullying and self-esteem. Findings demonstrate that self-disclosure behaviours are associated with bridging social capital and that presentation of the real self is associated with the benefits of both bonding and bridging social capital. In terms of risk outcomes, self-disclosure behaviours are associated with cyberbullying perpetration and victimisation. These findings highlight that 7- to 12-year-olds are accessing SNS and that their behaviours online are associated with both risky and beneficial outcomes. Importantly, parents, teachers and policymakers should consider the benefits of SNS use, as well as the risks, in order to foster children's digital engagement.