The EMODnet (European Marine Observation and Data network) Geology project ( http://www.emodnet-geology.eu/) collects and harmonizes marine geological data from the European sea areas to support decisionmaking and sustainable marine spatial planning. The partnership includes 39 marine organizations from 30 countries. The partners, mainly from the marine departments of the geological surveys of Europe (through the Association of European Geological Surveys- EuroGeoSurveys), have assembled marine geological information at a scale of 1:100 000 from all European sea areas (e.g. the White Sea, Baltic Sea, Barents Sea, the Iberian Coast, and the Mediterranean Sea within EU waters). This data includes the EMODnet seabed substrate map at a scale of 1:100 000 from the European marine areas. Traditionally, European countries have conducted their marine geological surveys according to their own national standards and classified substrates on the grounds of their national classification schemes. These national classifications are harmonized into a shared EMODnet schema using Folk's sediment triangle with a hierarchy of 16, 7 and 5 substrate classes. The data describes the seabed substrate from the uppermost 30 cm of the sediment column. The data has been generalized into a target scale (1:100 000). The smallest cartographic unit within the data is 0.05 km2 (5 hectares). Further information about the EMODnet-Geology project is available on the portal ( http://www.emodnet-geology.eu/).