Abstract: This paper discusses current efforts of the city of Seoul to grapple with some of its most pressing sustainability problems through conjoint social and governance innovations. Drawing on pertinent strands of urban-, transition-, and resilience-studies, it reviews the design and implementation of activities aimed at establishing a self-organizing social innovation ecosystem nurtured by place-based networks at neighborhood scale ("village communities"), and reflects on their potential to effectively enable wider sustainability transition dynamics. The case shows a relevant potential in that it demonstrates a civil-society and policy-driven experimental approach to fostering bottom-up community initiatives in a variety of sustainability-relevant domains, linking e.g. education, consumption, energy, construction, green space, cohesion and local economies. Through empowerment, networking and learning-by-doing at various urban scales, such deeply embedded urban innovation 'niches' could play a crucial role with a view to providing alternative solutions, discourses, lifestyles and related learning opportunities that can underpin the transformation of multiple socio-technical and social-ecological systems in parallel. Yet, in addition to successful individual initiatives this would also require to further develop shared visions and expectations, to create linkages between village communities and incumbent regimes, as well as to conceive of a strategy for dealing with the emerging spatial disparities at the scale of the metropolitan area.Conceptually the Seoul case study thus also traces some of the limitations of current (urban) transition research. By looking at the formation stage of urban social and governance innovations in the context of an Asian megacity, it draws attention to interactions between forms of agency, processes and domains mostly discussed in separation from each other, and/or without a clear account for their local embeddedness and the scalar relations within cities. In turn, this underlines the significant potentials inherent to cities for building transformative capacity, as well as some of the options available for urban governance, policy and planning related to this.