Healthy coastal and marine ecosystems have a vital role to play in climate mitigation and adaptation. Yet key barriers remain in the implementation of nature-based solutions for climate action, particularly around these four pillars: 1) science/knowledge; 2) capacity; 3) governance; and 4) financing. This COP27 side event will look at the critical gaps that exist around these four pillars and that are hindering the ability of ecosystems to fully play their role in climate adaptation and mitigation. It will explore the role of multi-partner initiatives and frameworks to address these gaps at different scales. The outcome of the event will be to develop a short statement of the key conditions of success for marine ecosystem-based resilience to support climate action. These conditions of success will be promoted and communicated throughout COP27 and beyond.