Despite the climate change commitments made under the landmark Paris Agreement in 2015, the world will continue to experience negative climate impacts. As such, pre-emptive adaptation planning is necessary to build and sustain countries’ social, economic and environmental resilience. For vulnerable coastal and island states, this can be done through the enhanced sustainable management, restoration and conservation of their marine and coastal ecosystems. Ecosystem-based adaptation (EbA), when used with other regulatory and legislative instruments, can harness ecosystems and ecosystem management to reduce countries’ vulnerability to climate change and secure a continued supply of ecosystem services to support broader sustainable development goals. However, despite the recognition of their value, the modification and degradation of these crucial habitats has continued unabated, and marine and coastal ecosystems are still largely absent in climate change response measures. It is crucial that EbA be more fully integrated into national and sectoral policies, as well as budgetary and regulatory frameworks, particularly in small island states and developing countries with vulnerable coastal areas. The advancement of national climate adaptation strategies and the revision of countries’ Nationally Determined Contributions (NDCs) in 2020 is an important opportunity to include marine and coastal ecosystems in official climate change response policies.