As cities are increasingly experiencing climate change impacts, a rise in transnational networks for climate-sensitive cities can be seen. To date, little is known about the effectiveness of these networks and how they facilitate city-to-city learning. By using insights from the policy transfer and policy learning literature, we aim to examine how networks for climate-sensitive cities facilitate policy learning and how this leads to policy transfer. To this end, we researched the European Interreg project BEGIN, in which ten local governments are exchanging lessons for creating Blue and Green Infrastructure (BGI) as subset of nature-based solutions for urban climate adaptation. Our findings demonstrate how the horizontal network enabled joint sensemaking, in which common themes regarding BGI were defined leading to policy inspiration between cities. City partners were identified as frontrunners, which spurred policy transfer to other city partners. Although the network would provide resources required for successful learning and transfer, commitment and authority still have to be found and the absence of clear learning deliverables made learning not a priority for the participating governments. Networks can become more effective by defining learning deliverables upfront, and the projects provided by the city partners should appeal to all partners in the network.