The issue of urban vacancy is both a complex and a prevalent phenomenon in multiple contexts globally, providing an opening to address systemic issues of precarity. In this article, I explore the issue of urban vacancy in São Paulo, where the problem of vacant property has been highlighted for years alongside housing challenges and socio-spatial segregation. While São Paulo’s real estate market is often unreachable for the urban poor, a Brazilian constitutional directive on the social function of property – the obligation to use property to further the common good – enables municipalities to take punitive action against owners of vacant property through a triad of policy tools. Therefore, despite the often-exclusionary nature of vacancy, transformational possibilities may exist. Exploring the application of these tools, I view urban vacancy through a perspective on common property, untangling emergent contestations and opportunities for transformation.