Multibeam echosounder data and seabed sampling data acquired during the INFOMAR and INSS national seabed mapping programmes were the primary sources of data used in the generation of this Collated Seabed Substrate layer. The original classes assigned to the data were translated to a modified Folk class to facilitate a seamless reclassification of the data to the EUNIS classification system. This map of ground type, together with data collated from other habitat mapping projects and seabed surveys, were integrated in a GIS to produce a single, harmonised layer of substrate distribution within the Currently Designated Irish Continental Shelf of the North Atlantic Ocean. Data used to collate the seabed substrate from surveys between 1999 and 2011. Collated seabed substrate calculated from seabed survey data gathered. The collation work was carried out as part of the Mesh Atlantic project, the objective of which was to produce a single, broadscale, habitat map of the Currently Designated Irish Continental Shelf Area. Data collected and created by the Advanced Mapping Services team of Ocean Science and Information Services (OSIS) within the Marine Institute (Ireland). Collated seabed substrate complete for areas surveyed under the INFOMAR programme and its predecessor INSS. Uncompleted areas include North Atlantic Ocean and Celtic Sea.