This study investigates how final year pre-service teachers (PSTs) from several countries use social media to support their online professional learning network (PLN) activities. Adopting a mixed-methods approach, it uses a global survey and interview methods to generate fresh insights into PSTs' informally-developed online PLN practices and their perceived benefits of these self-initiated activities. Findings uncover new understandings of contemporary PSTs' patterns of use and configurations of their online PLNs and have implications for their effective transitioning into the teaching profession. Implications for practice or policy: (1) Teacher educators should encourage pre-service teachers to informally develop their own online professional learning networks to leverage a range of benefits, driven by the authentic, diverse and accessible nature of ideas and materials encountered in these spaces; and (2) Pre-service teachers need affirmation and support to be confident, active participants in their chosen online professional learning network spaces, especially in networks shared with more experienced, practising teachers.