This dataset is the complete collection of the British Geological Survey (BGS) held Marine Survey data. The data held includes digital data and analogue records, plus associated physical sample material. Data are stored within the National Geosciences Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. BGS have collected Marine Survey data since 1966 and have also been provided with a range of third-party data. The data includes geophysical data (seismic reflection, side-scan sonar, multibeam echosounder bathymetry and backscatter, gravity and magnetics) and sample data from boreholes, cores and seabed grabs (logs, geological descriptions, geochemical, particle size analysis and geotechnical data). The majority of surveys are within the United Kingdom Continental Shelf (UKCS) area. Individual survey data coverage varies, depending on survey type (sampling, geophysics, multibeam or multi-disciplinary) and objectives (regional or local, shallow or deep). These data are applicable to a wide range of uses including environmental, geotechnical, geophysical and geological studies. Data are delivered via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm. Additional data are available on request enquiries@bgs.ac.uk.