Marine Ecosystem Restoration (MER) is a strategic pillar of European ocean governance, supporting biodiversity recovery, climate mitigation, and the long-term sustainability of the Blue Economy. In line with the EU Nature Restoration Regulation (NRR) and the EU Mission “Restore our Ocean and Waters by 2030”, this Policy Brief outlines key actions needed to scale up effective and durable MER across European seas. Evidence shows that restoration outcomes are strongest when active restoration measures are combined with long-term protection frameworks, including Other Effective Area-Based Conservation Measures (OECMs). This integrated “active plus passive” approach safeguards investments, enables recovery at ecologically meaningful scales, and ensures lasting benefits. Marine Protected Areas (MPAs) can contribute to facilitating MER by providing nurseries and opportunities for rewilding. To operationalise Article 5 of the NRR, Member States need robust ecological baselines, must implement standardised monitoring protocols and must adopt harmonised indicators of success. Coordinated EU guidance can enhance comparability while maintaining flexibility for local ecological and socio-environmental contexts. Scaling up MER requires increased and diversified financing, combining public funding with innovative instruments such as blue bonds and public–private partnerships. Given the potentially high return on investment.