First, the REFLOW Collaborative Governance Toolkit, outlines the design framework and overall journey which underpin the development of collaborative governance arrangements in the six pilot cities of the REFLOW project. Furthermore, it describes the core activities that, along the journey, will represent the concrete ground for collaborative governance experimentation and learning, and thereby the terrain for the development of specific tools and supporting resources which will feed the Toolkit over time. Lastly, this document also explains how the Toolkit is meant to be implemented over time in order to crystallize our progress and make it accessible to both the REFLOW partners and other interested cities and stakeholders. The current outlook of the Toolkit reflects a number of activities implemented in the first year of the project, including exploratory research on collaborative governance, pilot cities’ policy review, mapping of existing tools and guidelines for the circular economy in cities, analysis of the Pilot Cities Action Plans developed by the REFLOW Cities, as well as scoping out of their core challenges and opportunities.