This chapter critically engages with a range of literatures on urban sustainability transitions by focusing on the ways in which transitional strategies focused on eco-city projects become fluid across different geographical scales of enquiry. It explores a multilevel case study, focusing on the Sino-Singapore Tianjin Eco-City, an eco-city mega-project which has been under construction since 2007, and which is presented by the Chinese government as the flagship project within a wider context of central government support for approximately 200 transitional eco-city projects planned in China at the time of writing. The chapter establishes a dialogue between literatures on low-carbon sustainability transitions, urban socio-technical experiments, and the political ecology of scale. Specifically, the chapter argues for the need to spatialise studies of transition, by focusing on cities as sites and places within interlinked spatial scales. It draws some conclusions both in terms of the implications of spatialising studies of transition, and for conceptualising urban governance for sustainability.