Collaborative innovation is necessary to explore and implement circular economy strategies. Yet, empirical investigations into such collaborations are scarce. It is unclear whether the circular context creates differences or represents adaptions within how collaborative innovation is conducted. We draw upon strategic management and open innovation literature to highlight what is known about collaborative innovation and the types of innovation conducted. We use these insights to investigate explorative qualitative case research into how practitioners in the Netherlands have conducted collaborative circular oriented innovation. Our findings show that open innovation criteria can aid our understanding and analysis. Key managerial considerations relate to the incremental or systemic nature of the innovation pursued, which induce different collaborative projects and knowledge management structures. For incremental innovation, we observe phases of collaboration, whereas for more systemic innovation, we observe a more collaborative portfolio and layered approach. Furthermore, the more radical innovation pursuits that explore slowing or recovery strategies, especially beyond business-to-business arrangements, challenge companies. A crucial challenge remains related to how to develop and assess collaborative and system-oriented business models in the transition towards a circular economy. Finally, future research is needed to assess whether the current modes of collaborative innovation are sufficient to deliver a circular economy transition.