The purpose of this digital dataset is to provide accurate mapping of the distribution of sea-bed sediment types. Sea-bed sediments can only be mapped offshore, where the most recent deposits commonly form a veneer or superficial layer of unconsolidated material on the sea-bed. The dataset is produced for use at 1:250,000 scale. The boundaries between sediment classifications or types are delineated using sample station particle size analyses and descriptions, seafloor topography derived from shallow geophysical data and where available multibeam bathymetry and backscatter and side scan sonar profiles. The sediment types present on the sea-bed are of importance to a range of groups, including marine habitat mappers, marine spatial planners, the offshore construction and development sector, and the dredging and aggregate industries. These groups require detailed information on the nature of the sea-bed, including the sediment types present. The DiGSBS250k dataset has been created as vector polygons and are available in a range of GIS formats, including ArcGIS (.shp), ArcInfo Coverages and MapInfo (.tab). More specialised formats may be available but may incur additional processing costs.