The Clearing House Mechanisms (CHM) is a fundamental institutional component of the new Biodiversity Beyond National Jurisdiction (BBNJ) Agreement. The CHM plays an enabling role across the treaty, performing key data and knowledge-sharing functions concerning marine genetic resources, area-based management tools, environmental impact assessments, and capacity-building and technology transfer. Within the Preparatory Commission, States are considering the modalities of the CHM in preparation for the first COP. Unsurprisingly, a key focus of the literature is the effectiveness of different design options. However, the effectiveness of the CHM will also depend on how states and other actors interact with the mechanism, including the nature of data and information they can provide. This paper maps the role of the CHM across the treaty and considers the science needed to support its functions. The CHM has a broad mandate, which includes enhancing transparency, cooperation and capacity building. In anticipating the science needs of the CHM, it is therefore important to think beyond environmental, technology and data-science requirements. Identify pathways to enhance science diplomacy and knowledge pluralism will be equally important to support the CHM’s broader objectives and enhance the protection of biodiversity in high seas areas.