Objectives. The social construction of breast cancer (BC) survivor identity has produced a powerful image of woman as survivor. Group membership through peer-support programmes can provide positive role models, shape survivor identity and promote post-traumatic growth (PTG). The main objective of this study was to conduct a qualitative investigation based on a phenomenological framework in order to understand the lived experience of BC survivors participating in a peer-support programme based on a challenge event. Design. This is a qualitative semi-structured and written narrative study. Interviews were subjected to interpretative phenomenological analysis and the written narratives via thematic analysis. Method. Interviews were conducted with 27 participants who were new to the peer-support event for women diagnosed with BC, and 10 participants who had taken part in multiple events provided written narratives of their experience. Interviews and surveys were completed pre- and post-event. Results. Important elements of the peer-support environment included a safe network of other survivors, which provided understanding and acceptance. Overcoming challenges during the event and the opportunity to bond with positive role models affirmed a strong survivor identity and promoted PTG. For some participants, a shift in identity was evident with a newfound positive identification with the term BC survivor. Conclusions. Peer-support programmes based on challenge events have the potential to extend the type of supportive care that is available for women diagnosed with BC by providing an alternative to the traditional support group format. 鲰10 The British Psychological Society.