Assessing subnational contributions to maritime spatial planning: ex-post application of a diagnostic framework in sixteen European cases across four sea basins

Maritime Spatial Planning (MSP) is a central instrument for implementing the EU’s ecosystem-based and integrated maritime governance agenda, yet its implementation depends on national administrations, which are often characterised by, and reliant upon, unevenly empowered and resourced subnational authorities. This paper addresses the lack of systematic cross-regional approaches for assessing subnational contributions to MSP by proposing the Regional Assessment for Maritime Spatial Planning (RAMSP), an indicator-based framework capturing six dimensions of subnational involvement: Governance, Stakeholder Engagement, Technical Capacity, Policy Integration, Cooperation, and Conflict Resolution. RAMSP is tested ex-post by applying the indicators to triangulated evidence from the EU funded REGINA-MSP project (survey, interviews and document-based institutional mapping), covering 16 subnational entities from 12 EU Member States across four major sea basins. Results indicate that formal positioning has advanced further than operational capability: Governance and Policy Integration are comparatively stronger on average, while enabling capacities remain uneven, especially Cooperation, alongside weaker development of MSP-specific tools and conflict mediation mechanisms. Cross-dimensional correlations are consistent with subnational capacities tend to co-vary as recurrent “bundles”, rather than developing independently, and a four-tier typology (Nascent, Emerging, Established, Exemplary) highlights distinct combinations of authority, information infrastructure, and coordination capacity. The paper concludes with recommendations directed to national competent authorities, regional administrations, and EU-level support mechanisms, emphasising a shift from creating formal roles towards strengthening resourcing, interoperable data and tools, and institutionalised sea-basin cooperation to improve MSP implementation and review.