Building on the World Bank's Blue Economy approach, which calls for the sustainable and integrated development of economic sectors in a healthy ocean, this report presents lessons learned from expanding the knowledge base around Blue Biodiversity and then applying it. The report also highlights ways that MPAs and OECMs can promote the equitable and inclusive participation of Indigenous Peoples and local communities (IPlc), women, youth, and other underrepresented people in marine management. In sum, this report aims to communicate what, why, and how of using spatial management to preserve marine assets and ocean vitality, highlighting best practices across the main tools and approaches. The document is modelled on other PROBLUE publications, and links to previous World Bank guidance on MSP and Blue Carbon. The authors hope it will encourage Member States to give detailed attention to marine biodiversity as they work to meet conditions of World Bank loans and their commitments under UNFCCC, the Global Biodiversity Framework, and other global goals and agreements. The intended outcome is the mainstreaming of Blue Biodiversity in government policies, harnessing the full range of financing to invest in marine management and building lasting support for protection of the world's marine ecosystems.