Cities' role in addressing both climate change mitigation and adaptation is becoming increasingly important. Within the last decade, cities together with other actors have initiated neighborhood-level climate change projects that build on the concept of experimentation using participation and coproduction. Common features in these initiatives are the limitation of the project to a geographically specific area within the city, inclusion of stakeholders from that physical location, and the use of different types of experimentation through participation in order to pursue climate objectives. This qualitative case study discusses the participatory experimentation and potential structural transformations by focusing on the Climate Street project of Helsinki and Vantaa, Finland. More specifically, we examine how learning, participation, and public visibility contribute toward the impact of the project. Our results show that existing urban governance structures restrict experiments in many ways and only certain types of change are feasible. This implies that while participatory experimentation offers promise but is not a panacea in terms of governing climate change. K E Y W O R D S climate change, climate street, experimentation, urban governance 1 | INTRODUCTION Cities' role in addressing both climate change mitigation and adaptation is becoming increasingly important (Corfee-Merlot, Cochran,