The dataset comprises hydrographic measurements including current velocity, temperature, salinity and sea level data. Results of one iodine experiment are also included. The data were collected in the area of the Faroe Islands, Shetland, the Norwegian Sea and the Barents Sea between May 2000 and November 2001 over a series of 31 cruises using the research vessels Scotia (UK), Magnus Heinason (Faroes), Johan Hjort and G.O.Sars (Norway). Measurements included five repeated conductivity-temperature-depth (CTD) sections in the Faroe Shetland Channel, North of Faroes, Gimsøy and Svinøy and Fugløya - Bear Island. Fifty one moorings containing current meters, acoustic Doppler current profilers (ADCPs), bottom pressure recorders and inverted echosounders were deployed along the sections. Ten RAFOS floats were also deployed in the Lofoten Basin to measure Lagrangian currents. During the Johan Hjort cruise in May 2000 about 300 water samples were collected in order to measure 129Iodine concentration (relative to 127I). Analysis was carried out by the Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, France. Observational data from the standard tidal stations at Tórshavn, Lerwick, Bodø and Ny-Ålesund were also used in the analysis. The main objective of MAIA was the development of an inexpensive, reliable system for monitoring the inflow of Atlantic water to the northern seas, based on coastal sea-level data. The project involved contributions from a number of international institutions. The resulting data set was collated at BODC and published on CD-ROM in March 2003.