This chapter discusses the potential transition from linear to circular economy providing a concise overview of circular economy. It adopts the extended ‘circular city’ concept beyond mere circular economy and proposes to incorporate the staggering amount and variety of city assets and products available in cities. The chapter combines them with various circular actions to determine the enormous potential, which constitutes circular cities. The chapter also illustrates how to generate circular actions in cities by referring to examples and proposes a unified pragmatic stepwise methodology to implement circularity in urban contexts. Four clear steps of the methodology are described for practitioners and a number of non-exhaustive auxiliary means are listed. Examples are provided to demonstrate the use of circularity auxiliary means in practical urban implementations. The proposed methodology aims to prioritise circularity actions towards the achievement of carbon emissions reduction and can be revised over time as the cities progress. Further research areas and the immense potential available to cities for its application are also mentioned which can enhance the application of the proposed methodology. The chapter lists a set of observations as concluding remarks and presents a brief overview of the proposed methodology.