Transitioning towards a circular built environment and turning waste into resources have become one of the new sustainability paradigms today. However, a circular transition can be considered a ‘wicked problem’. The multiple dimensions and scales of the circular transition and its substantial spatial implications fit well into the planning approach of Geodesign. The Horizon 2020 funded project “Resource Management in the periurban Areas - Going beyond Urban Metabolism (REPAiR)” implemented an innovative Geodesign approach. Moreover, it explored its capability to support spatial decision-making processes for the circular economy transition of the built environment within urban planning practices. This article aims to understand to what extent a process of Geodesign, which is conducted with the support of a digital tool and a Living Lab approach, can support the creation of localised circular economy strategies and foster the circular economy transition in cities and territories. The analysis explores and compares the results of three European cases -Amsterdam, Hamburg and Naples. It considers the kind of data input required to run the process in every phase, the stakeholders involved and their typology, the specific urban or territorial, planning and governance scales of analysis, and the final output definition after the Geodesign process implementation. The approach outputs constitute a decision support system for easing negotiations between local actors regarding the circularity strategies to implement. The findings reveal an intertwinement between different forms of knowledge included in the process, ranging from sustainability to governance and design, and the actors engaged in planning a circularity transition spatially. However, even using similar starting data, the local information and the starting conditions strongly influence the process and the types of strategies elaborated in each case.@en