Seascapes are large, multiple-use marine areas, defined scientifically and strategically, in which government authorities, private organizations, and other stakeholders cooperate to conserve the diversity and abundance of marine life and promote human well-being. This approach has been applied by global nonprofit partnerships in five seascapes across eight countries and has drawn on the practical experience of more than 250 partners over 15 years. These experiences have helped define the Seascape approach, consisting of nine essential elements, for achieving effective ocean governance and management from local to regional levels. Lessons learned relate to using integrated planning frameworks, community-led and locally owned initiatives, and a network of partners and a “backbone” organization for effective Seascape planning and design; promoting diversification in funding sources, private sector engagement, and the transition of nonprofit roles to ensure durability of a Seascape; and ensuring Seascape outcomes are measured through robust monitoring and evaluation frameworks and communicated effectively. Seascapes are unique in their ability to create a pathway toward sustainable development. To ensure support and amplification of the approach, they must align with diversified funding opportunities and global priorities outlined in international United Nations conventions focused on sustainable development and ocean health.