Operationalizing marine multifunctionality in Europe: Policy mixes, activation modes, and governance functions

Marine multifunctionality, understood as the intentional combination of uses in the same marine space, is increasingly promoted in European policy, yet implementation remains uneven. This study asks which combinations of governance instruments have enabled the operationalisation of marine multifunctionality in Europe, and under what conditions. Using systematic review principles, we synthesise peer-reviewed evidence published between 2007 and 2025 across European sea basins. Guided by a policy mix perspective, we classify instruments into four families – legal, economic, spatial planning, and techno-digital – and examine how they are activated in practice, the functions they perform, and how they are sequenced across governance levels. We further interpret how cases align with three modes of multifunctionality: co-use (shared structures), co-location (spatial proximity), and co-existence (compatible operations). The results show that successful cases assemble policy mixes that first establish spatial and legal clarity, for example through marine spatial planning and coexistence provisions; then address risk through safety zones, liability, and compensation; and finally enable implementation through targeted finance, pilot projects, and monitoring or technical solutions. The most advanced configurations cluster in the North Sea, where energy-led mixes dominate, while Mediterranean examples more often centre on fisheries-tourism-conservation pathways. Where progress lags, missing functions, weak alignment between plans and permits, or unstable rules are common. These findings lead to three recommendations: package instruments ex ante where possible; run pilots under provisional conditions; and embed monitoring and cumulative-effects assessment in licences so that learning feeds back into marine spatial plans and related sectoral frameworks.