Are you engaged in climate adaptation in the city in a professional capacity? Then you are aware of the importance of collaboration with various stakeholders. But how can you find out what exactly they need? And what is the best way to collaborate? The SPONGE2020 toolbox) will provide you with answers. The toolbox is the result of a European project involving many years of collaboration between Dutch, Flemish, and British government bodies. All the expertise and experience generated by this collaboration has been amassed in this toolbox. It contains information on all the parties required for an integrated pursuit of climate adaptation in the city, such as local residents, government authorities, businesses, NGOs, housing corporations, and educational establishments. Furthermore, SPONGE2020 has developed a step-by-step plan for optimum collaboration with other stakeholders and for garnering more commitment to a collective project. Would you like to know how this works in actual practice? Take a look at one of the SPONGE2020 pilot projects in the toolbox.