We succeeded in obtaining the depth profile of 236U for a sampling station in the Northeast Pacific Ocean using only one litre of seawater sample from each depth. For this purpose, a new procedure was developed that allowed for the preparation of accelerator mass spectrometry targets for trace uranium using only 100 μg of iron carrier material. The 236U concentrations in water samples from the Northeast Pacific Ocean showed large variations from (9.26 ± 0.42) × 106 atoms/kg at 60 m depth to (0.08 ± 0.02) × 106 atoms/kg at a depth of 3000 m. The high 236U concentrations in surface water reflect the input of 236U by global and local fallout from nuclear weapons tests. The low 236U concentrations in seawater from 1500 m and below are an indicator for the low vertical diffusion of surface water to deeper layers in the North Pacific Ocean. The total inventory of 236U on the water column was (8.35 ± 0.23) × 1012 atoms/m2, which is lower compared to those of other ocean regions solely affected by global fallout on comparable latitudes. This study represents the first dataset for 236U in the Pacific Ocean and shows the possibility of downsizing sample volumes which may help in future applications of 236U as tracer for large ocean areas.