In policy and practice, urban Nature-Based Solutions (NBS) are considered promising innovations for sustainable urban transformation. NBS are interventions that use nature to address multiple sustainability challenges simultaneously. As such, they present a novel perspective on urban land use and development. Yet their current uptake into urban development lags behind EU ambitions. Drawing from transitions studies, this paper suggests that the limited uptake of NBS innovation stems from structural conditions that keep urban development systems locked in their current state, thereby favouring traditional ‘grey’ development. With a systematic literature review, we identify preliminary structural conditions that likely affect the uptake of urban NBS, culminating in a framework of ‘urban infrastructure regimes’, which we then illustrate with two European examples of urban NBS. Our findings indicate the relevance of using a transitions studies perspective for generating insights into the structural conditions – knowledge base, policy paradigms, etc. – that underlie barriers and opportunities for NBS uptake. We particularly argue that identifying the state and obduracy of these conditions provides a deeper understanding of how NBS uptake takes place. Findings also suggest that nature-based innovations require a customised transitions framework that accounts for the role of physical geographies.