<p>Collaboration is deemed increasingly relevant in the context of environmental topics by policymakers, advocates for new modes of scientific knowledge production and funders. However, there are several issues and obstacles that hamper projects in which practitioners of different disciplines work together. In this regard, the potentially productive role of boundary objects/concepts that allow for collaboration and coordination among groups with heterogeneous interests has been recognised. This paper approaches interdisciplinary collaboration from the perspective of an international research project that focused on circular bioresource flow across and between sectors of the bioeconomy. Based on observations during the project’s design and implementation phases, the paper explores the role of boundary objects/concepts in interdisciplinary collaboration. We conclude that boundary objects can facilitate pragmatic collaboration, but, without social interaction and engagement in the context of specific data gathering activities, this may lead to black-boxing and disciplinary segregation. Furthermore, our experience suggests that expectations surrounding interdisciplinarity must be tempered and the actual practice and social dynamics of interdisciplinarity in project-based research must be studied and discussed to uncover practical insights that can aid future projects tackling pressing environmental issues.</p>