Co-creation is often presented as a solution to challenges of achieving energy transitions. However, there is currently little known about how coordinating stakeholders, such as city administrations, interpret co-creation and the extent to which this influences co-creation processes. We draw on a recent project, which embedded co-creation in public decision-making about local-level, sustainable heating transitions. We specifically address the question of how co-creation has been interpreted and implemented by administrations in two major Belgian cities, Bruges and Mechelen, between 2019 and 2023. Data collection included expert interviews, participatory observation, workshops, focus groups, and reviews of action plans and policy documents. We found that a normative understanding of co-creation evolved amongst the project coordinators, who inherently valued the inclusion of citizens in sustainable heat transitions, although actual co-creation only took place at the end of the project (2022–2023). However, we observed structural impediments and contexts that impinge on co-creation: a perceived conflict between community engagement and existing policy agendas, departmental interests; the instrumental framing of projects and the role of co-creation; and the impact of wider political pressures and events (in this case the COVID-19 pandemic restrictions). Conclusions are drawn regarding the longer-term benefits of co-creation for coordinating stakeholders. We also stress the need for research to more fully attend to the structural relations that enable and constrain these actors to practice and innovate with co-creation.