The ocean represents a fundamental source of micronutrients and protein for a growing world population. Seafood is a highly traded and sought after commodity on international markets, and is critically dependent on healthy marine ecosystems. A global trend of wild stocks being overfished and in decline, as well as multiple sustainability challenges associated with a rapid growth of aquaculture, represent key concerns in relation to the United Nations Sustainable Development Goals. Existing efforts aimed to improve the sustainability of seafood production have generated important progress, primarily at the local and national levels, but have yet to effectively address the global challenges associated with the ocean. This study highlights the importance of transnational corporations in enabling transformative change, and thereby contributes to advancing the limited understanding of large-scale private actors within the sustainability science literature. We describe how we engaged with large seafood producers to coproduce a global science-business initiative for ocean stewardship. We suggest that this initiative is improving the prospects for transformative change by providing novel links between science and business, between wild-capture fisheries and aquaculture, and across geographical space. We argue that scientists can play an important role in facilitating change by connecting knowledge to action among global actors, while recognizing risks associated with such engagement. The methods developed through this case study contribute to identifying key competences in sustainability science and hold promises for other sectors as well.coproduction | governance | learning | resilience | transformation S ustainability science is becoming a mainstream scientific approach for understanding and addressing the global and interconnected challenges currently facing humanity (1, 2). A key component of sustainability science is to collaborate with actors outside of academia to codesign and codevelop an understanding of the challenges and their corresponding solutions (2, 3). Local and regional examples illustrate how sustainability scientists have engaged with society as change agents (4, 5) and the challenges associated with such engagement (3,4,6,7). In this context, however, there has been limited attention devoted to large-scale private actors (8). Existing studies primarily focus on how major brands invest in-and benefit from-sustainability initiatives (9), or analyze how and when voluntary commitments to sustainability may influence corporate behavior (10, 11). Little is known about how scientists can engage with corporations and how knowledge can be transferred from science to action by the private sector.In the following, we present our experience from a coproduction process with large transnational seafood corporations, aimed at stimulating transformative change in the seafood industry, and the subsequent emergence of a global initiative for ocean stewardship. Here, ocean stewardship is viewed as an adaptive and lear...