Abstract
Highly and fully protected marine protected areas (HF-MPAs) deliver the strongest ecological outcomes, yet they cover just 3.8% of the ocean, and annual gains have stalled. We combine ProtectedSeas regulatory classifications with coastal habitat maps for corals, mangroves, seagrasses, and saltmarshes to track HF-MPAs and minimally/lightly protected MPAs (ML-MPAs) from 2000 to 2025 and overlay results with governance-based enabling conditions. HF-MPAs remain rare even in high-capacity countries that host most mapped coastal habitats and 39% of the global upgrade gap. Upgrading ML-MPAs in this small cohort-especially in overseas territories-offers immediate habitat protection gains and a visible pathway toward 30 × 30, while parallel efforts expand high-quality protection in open-ocean and deep-sea ecosystems and build enabling conditions elsewhere.