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 stable water isotopes 18O & 2H samples 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. Samples for analysis of water isotopic were collected at 1, 5, 10, 20, 30, 50, 75, 100, 150, 200, 250, 500 m depth in the water column at each station. Stable isotopes of oxygen and hydrogen (16O, 18O, 1H, 2H) in water samples were determined using a Cavity Ringdown Spectrometer, L2130-i Isotopic sH20 (Picarro Inc., USA).

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