Communication and collaboration are critical for designing and implementing responses to climate change impacts and related disasters. This acknowledgement has increased interest in understanding social and institutional networks for climate change adaptation (CCA) and disaster risk reduction (DRR). In this study, we used Social Network Analysis (SNA) to explore institutional interactions within and across the communities of the aforementioned domains in Europe. Firstly, we investigated the type and intensity of interactions. We calculated SNA metrics to assess the roles of different actors and applied cluster analysis to identify actors with similar patterns of connections. SNA showed that communication is often more intensive within the two communities, while collaboration is frequent around topics related to both CCA and DRR. Cluster analysis revealed that actors tied with DRR were more closely connected, while actors tied with CCA and those with mixed connections showed no obvious clustering affinity. The European Climate Adaptation Platform, Climate-ADAPT, had the highest value for various SNA metrics, reflecting its popularity in the network and its potential for enhancing interactions among its actors. Finally, SNA was complemented by qualitative interviews, which emphasised the importance of connecting CCA and DRR in organisational mission and vision statements.Sustainability 2020, 12, 1275 2 of 32 transformative responses, and a good understanding of the social and institutional structures is critical for catalysing them.At the community level, communication and collaboration have proven to be crucial in preparing for, responding to, or recovering from climate-related hazards [5][6][7]. People who are well connected to their networks have better access to knowledge, resources, and skills, and can provide or receive prompt support (e.g., physical, economic, psychological). The importance of social capital (which is defined as "[ . . . ] the institutions that help us maintain and develop human capital in partnership with others; e.g., families, communities, businesses, trade unions, schools, and voluntary organisations" (https://www.forumforthefuture.org/project/five-capitals/overview)) in such circumstances was lately demonstrated during the post-Hurricane Sandy recovery phase [8,9]. People living in neighbourhoods with more social resources and connections were, and perceived themselves as, more resilient, even in cases where available financial resources were low [10].At the institutional level, recent policy developments, such as the EU Adaptation Strategy [11], the Paris Agreement [12], the Agenda 2030 for Sustainable Development [13], and the Sendai Framework for Disaster Risk Reduction [14,15] have underlined not only the importance of adaptation and risk reduction, but also the co-benefits that may arise from aligned policies and action [16][17][18][19]. Legal and institutional frameworks undoubtedly play a critical role in creating an enabling or inhibiting environment for developing synergies bet...