This dataset contains 151 conductivity, temperature, and depth (CTD) casts taken during a summer 2023 Arctic expedition, led by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research. The casts were recorded offshore of the northern and southern coastlines of Tuktoyaktuk Island (Northwest Territories, Canada), as well as an offshore seabed channel approximately 20 km northeast of Tuktoyaktuk Island. The measurements were part of the "DEPTHAW Field Campaign" within the "Modular Observation solutions for Earth Systems" (MOSES) program. The data provides primary seawater variables, including water temperature, electrical conductivity, and pressure, at various points in the water column and at different points in space. The data was processed to isolate downcast data and calculate water depth (from pressure).