Nature-based solutions (NbS) have been put forward as an approach to meet many of the challenges facing cities globally, such as increased temperatures, flooding and loss of biodiversity. Co-creation is a central part of the NbS approach, with the use of urban living laboratories (ULLs) as a mechanism for supporting co-creation processes. In this perspective essay, we will reflect on the potential for knowledge co-creation of NbS within an ULL context, based on the experiences from the EU H2020-funded projects REGREEN and CONEXUS. Furthermore, we will discuss how NbS and ULLs have the potential to contribute to transformative change. This is done through elaborating on processes of knowledge co-creation, communication and learning, as well as discussing the impacts which REGREEN and similar projects could have, focusing on the role of local governmental agencies.