Total (dissolved + particulate) Th-234 and U-238 activities in seawater in the Labrador Sea from 19 May to 2 June 2022 during the BELAS-1 expedition (CE22009, RV Celtic Explorer). Water column samples were taken in the upper 500 m using a CTD-rosette at 15 discrete depths. Unfiltered seawater samples (2 L) were processed on board and analyzed for the activity of total Th-234 following the method described in Clevenger et al. (2021). The U-238 activity was derived from salinity (Owens et al., 2011).