This data set comprises hydrographic measurements including temperature, salinity, fluorescence, attenuance, dissolved oxygen concentrations and current velocities. Water samples were also collected for salinity and geochemical analysis, and the data set also includes bathymetric, sediment and upper ocean turbulence measurements. The data were collected over six Science Missions at the Strait of Sicily, West Coast of Scotland (Loch Etive and Loch Fyne), North-East Scotland and Shetland Islands, North Weddell Sea, Isles of Scilly, Southern North Sea (Norfolk Bank) over the period 19 April 1999 – 25 May 2001. The data were collected by both shipboard sensors and those attached to the Autosub (Autonomous Underwater Vehicle) package. Shipboard data collection included deployment of a conductivity-temperature-depth (CTD) package with attached auxiliary sensors. Lowered acoustic Dopper current profilers (LADCPs) were also attached to the CTD frame, while discrete water samples were collected from the CTD stations. Oceanographic, bathymetric and sediment data were collected along the ship’s track. Autosub measurements included standard environmental parameters and acoustic instruments were used to measure ocean bottom relief at high resolution. A camera was also attached to the vehicle, permitting the collection of detailed photographs of the seabed. The broad aims of the Autosub Programme are the collection of interdisciplinary data sets that cannot be obtained by research ships, and demonstration to the scientific and wider user community of the usefulness of an AUV. Investigators: David A Smeed, Kate Stansfield, Julian Overnell, Kenny D Black, Peter Statham, Chris German, Andrew S. Brierley, Paul G. Fernandes, Mark A. Brandon, Alex Cunningham, Peter Burkill, Glen Tarran, Prof. Mike Collins, Dr George Voulgaris, Dr John Trowbridge, Dr Eugene Terray, Steve A Thorpe and Thomas Osborn. The British Oceanographic Data Centre holds the Autosub navigation files, CTD and ADCP data for each of the missions listed above. The data are contained as high resolution time series. The data are presently being processed and have not been fully quality controlled. The Autosub science missions brought together researchers and engineers from a number of UK institutions, with the project being coordinated by the National Oceanography Centre, Southampton.