This dataset is a compilation of the data on delimitation of marine waters that Member States reported (in shapefile ‘SHP’ format) to the European Commission as part of their implementation of the MSFD. The dataset is split by EU Member States and by type ("water-column and seabed" areas and "seabed only" areas). It includes the EU 27 Member States plus the United Kingdom (as MSFD reporting remained an obligation for the UK until 31 December 2021).

Member States reported single or multiple areas to represent their marine waters; where multiple areas were reported (as Marine Reporting Units for assessment reporting) these are aggregated to represent the total extent of the Member State’s marine waters for this dataset.

The "water-column and seabed" areas indicate the areas where the Member State which has reported them implements the MSFD both in the water-column and the seabed and subsoil. This typically includes:

a. Coastal Waters, as defined under the Water Framework Directive;

b. Territorial Waters, out to 12 NM (nautical miles) from the coastline excepting for the UK (Gibraltar) (3 NM) and Greece (6 NM), and

c. Exclusive Economic Zones, or other designations, out to the median line with adjacent countries or to coastline to 200 NM for some Atlantic Member States.

The "seabed only" areas represent continental shelf areas where the Member State which has reported them implements the MSFD only on the seabed and subsoil and which lie beyond where it implements the MSFD in the water column.

The “seabed only” areas extend beyond the 6 NM limit of the Territorial Waters (Greece and the 200 NM limit of the Exclusive Economic Zones (Ireland, Portugal, United Kingdom).

Compared to the first release (May 2020) of this Marine waters dataset this second version has the following notable differences in marine waters type:

- entire reported area by Malta is now considered as ”Water-column and seabed”.

The map should not be understood as representing international marine borders. To this end, the following disclaimer should always accompany the map: "This map serves as a working tool only and shall not be considered as an official or legally-binding map representing marine borders in accordance with international laws. This map shall be used without prejudice to the agreements that will be concluded between Member States or between Member States and non-EU states in respect of their marine borders.".

The boundaries of marine waters are those reported by Member States for the purposes of implementing the MSFD. There may be overlaps and gaps in the boundaries of adjacent Member States. This may be due to differing jurisdictional claims by the Member States concerned or may be more technical in nature (e.g., non-coincident boundaries of GIS shapefiles). Possible overlaps and gaps between the boundaries of Member State’s marine waters and neighbouring non-EU states are unknown.