Marine biodiversity is critical to the Blue Economy. It underpins ecosystem services that are vital for global functions such as climate regulation, fisheries management, and beach management for coastal protection and recreation. But unlike most land-based resources, oceans are more subject to open access than terrestrial resources. This can result in overexploitation by multiple users who may not even be aware of each other. This greatly complicates efforts to understand and manage cumulative impacts on biodiversity and ecosystem services (BES). Marine spatial planning (MSP) offers coastal countries a tool to address this challenge. It provides spatial mapping of BES and the threats they face, bringing together diverse users in a participatory, holistic approach that promotes the mainstreaming of BES into goals for other economic sectors. It allows for trade-offs between different oceanic sectors to help build a more sustainable approach for the use of common resources.