Here we present results from a synoptic survey of the pan‐east Greenland coastal system from the entrance of fjords at Cape Farewell (59°N) to Kaiser Franz Josef Fjord (73°N). Using conductivity‐temperature‐depth (CTD) profiles and water isotopes (δ18O, δ2H) sampling, we aim to describe the spatial distribution of water masses and source water fractions along east Greenland and their link to proglacial fjords.This is a hydrographic dataset containing CTD cast from the HDMS Knud Rasmussen cruise KR_2021 that took place from 10-26 August 2021 and was part of the research project Greenland Gradients led by Rysgaard, Sören. On each station, vertical CTD (SBE19plus) casts were made down to 500 m water depth or close to the sea floor if shallower. Temperature and salinity data were derived from these CTD profiles. Temperature is reported as potential temperature (ITS-90, degree C).

Additional funding: Award: 2021-01 from Danish Center for Marine Research (https://www.havforskning.dk,); Award: Greenland Gradient from Aage V Jensens Foundation (AVJCF) https://avjcf.org