There are divergent visions and practices of sustainable urban design in the context of contemporary processes of climate adaptation and infrastructural change. However, the key influences on what trajectory is adopted in different instances have yet to be explored in depth. This article highlights and explores an emerging connection between climate adaptation, sustainable urban design and regeneration or what is termed the ‘green adaptation regeneration nexus’. This is identified as an ambiguous phenomenon which could instantiate more integrated and collaborative models of planning or, alternatively, denote an intensified economic focus. The implications of the green adaptation-urban regeneration nexus are explored through two case studies of combined climate adaptation and regeneration projects in Sheffield and Copenhagen. The key finding is that both projects’ institutional setting within pre-existing regeneration planning frameworks has been a key influence in both enabling and constraining community participation. The article’s key contribution is to highlight the inadequacy of inherited and often flawed planning frameworks from the perspective of realizing innovative, socially and ecologically sustainable approaches to design in an increasingly important sector of urban planning and design practice.