Background: In this paper we examine the role of collective action in assisting rural communities to cope with and adapt to environmental risks in Nepalgunj, Nepal and Krabi Province, Thailand. Drawing upon two case studies, we explore the role of collective action in building adaptive capacity, paying particular attention to the role of social networks. Methods: Data for this paper was gathered using a range of different methods across the two different studies. In Nepal semi-structured interviews were conducted with a range of stakeholders in addition to participant observation and secondary data collection. In Thailand the researchers utilised a vulnerability assessment, participatory multi-stakeholder assessment, a detailed case study and an online dialogue. Findings: We make three key observations: firstly, collective action plays a significant role in enhancing adaptive capacity and hence should be more strongly considered in the development of climate change adaptation strategies; secondly, social networks are a particularly important component of collective action for the building of adaptive capacity; and thirdly, the mandate, capacity, and structure of local government agencies can influence the effectiveness of collective action, both positively and negatively. Conclusions: We argue that there is an urgent need for further consideration of the different forms of collective action within community-based disaster risk management and climate change adaptation.