It is increasingly recognised that social learning by teachers can stimulate professional development. In this study, we search for the social behaviour patterns which can act as a catalyst for professional development, with an explicit focus on student teachers' learning. Based on the 'Dimensions of Social Learning (DSL) Framework', including 4 dimensions and 11 indicators of social learning, the present study explores the social configuration of one network of primary teachers (n = 12), student teachers (n = 12) and teacher educators (n = 2). Two research questions guide this exploration: (1) What patterns of social behaviour in teacher networks are likely to lead to professional learning? (2) What network facilitation guidelines can be discerned to assist teachers and teacher educators wishing to optimise student teachers' professional development? Data collection consisted of video recordings, reflective notes and semi-structured interviews with network members. The findings paint a picture of how social learning in teacher networks is related to the group's social configuration. Observation criteria and student facilitation guidelines are suggested to support professional development within teacher networks. For each dimension in the DSL Framework, one point of attention is discerned to optimise students' learning in teacher networks.