Water vapour stable isotope composition (delta 18-O and delta 2-H) with respect to VSMOW have been measured continuously together with specific humidity, using a ship-mounted infrared spectrometer, during the INTAROS research cruise in August 2018 in the vicinity of Svalbard. In addition, stable water isotopes in precipitation, ocean surface water, and from CTD casts have been gathered at several occasions. The water isotope data are supplemented by continous measurements of meteorological parameters, including ambient pressure, air temperature, relative humidity, cloud height, visibility, wind speed, and wind direction, water temperature. All data have been collected during the INTAROS cruise on board KV Svalbard, lasting from 30 July to 18 August 2018. Water vapour isotope and meteorology data have been averaged at a 1 min resolution. The cruise started and ended at Longyearbyen, Svalbard, Norway, and covered part of the Fram strait to the west of Svalbard, and the Marginal Ice Zone north of the Svalbard Archipelago. A Picarro L2140-i water vapour isotope analyzer was installed onboard KV Svalbard during the INTAROS cruise with a heated inlet system at 10m above the ocean surface, flushed by a manifold pump at about 10 L per minute. Discrete water samples from precipitation were taken on an event basis in an open collector. Ocean surface water samples were taken from a bucket, and samples from CTD casts were taken from Niskin bottles. All liquid samples were analysed for delta 18-O and delta 2-H at FARLAB, University of Bergen, Norway. Data from corresponding CTD casts were used to extract salinity information at the depth of sea water isotope samples (doi:10.21335/NMDC-NERSC-1161526892). Meteorological data from the ship mounted meteorology payload have been provided by Meteorologisk Institutt, Oslo, Norway.