Climate change and its impacts cannot be addressed once for all due to internal complexity. Some implemented strategies may only be capable of dealing with a cluster of problems while leaving many others untouched. The co-benefits approach, however, opens up a ‘window of opportunity’ via achieving multi-goals simultaneously. Based on this, this paper aims to unpack the interrelationship between the struggling urban heat island (UHI) issue and the already ongoing sponge city (SPC) projects in China. Specifically, the co-benefits are investigated from technical, financial, institutional and social perspectives, after which pathways to implementation are presented. In these aspects, the co-benefits approach can bring opportunities for implementing SPC and UHI mitigation. The inclusion of UHI mitigation into SPC construction can enhance public participation and thereby consolidate the public-private partnership model for funds. During the co-benefits approach implementation, the weights of different authorities can be rebalanced to promote institutional transitions. SPC-derived UHI mitigation approach, potentially realising synergies of urban flooding and UHI mitigation, can be a model for countries which have already released low-impact development water management practices, and may also provide references for other projects such as green building, low-carbon eco-city, smart city, forest city and haze treatment for UHI mitigation.