The Yukon Coast Land Expedition was conducted in July 2023 along an active retrogressive thaw slump; active-slump (AS), and a non-slump (NS) transect up to 2000 m from the shore, near Herschel Island-Qikiqtaruk, in the Northwest Canadian Arctic. The aim was to investigate the the concentrations and isotopic composition (δ13C, 14C, and 15N) of DIC and POC in the water column. Additionally, isotopic analysis was done for the most abundant organisms in the different trophic levels within the Arctic Ocean's nearshore zone to determine organic carbon (OC) sources and utilization in the coastal food web. The surface water was taken at the upper 50 cm while the bottom water was taken at 50 cm above the sediment, using a USB 50050 water sampler. δ13C and δ15N were measured using an Elementar Vario EL Cube, interfaced to an Isoprime VisION IRMS (Elementar UK Ltd, Cheadle, UK) at University of California-Davis in the USA. δ14C was determined using Mini Carbon Dating System (MICADAS) accelerator mass spectrometer at the Alfred-Wegener-Institute, Bremerhaven in Germany.