Data sharing across organizational boundaries has become increasingly important for advancing the transition to circular cities. To establish a structured data-sharing effort among different actors, collaboration in cross-sector partnerships is needed. However, these partnerships face specific challenges, especially regarding the governance of data sharing. Through a qualitative analysis of cross-sector partnerships formed around the development of the digital product passport, we uncover the tensions associated with collaborative data-sharing governance in the context of circular cities. We also offer guidance to actors involved in urban transitions to the circular economy on how to address these tensions.