The penetration of dust clouds over a sea surface is modelled as a sediment transport-diffusion problem. The model is used to determine the steady state concentration field of two-dimensional dust clouds during offishore dust storms. The rates of dust deposition into the sea can then be calculated from the obtained concentration fields. The model was applied to offshore dust storms blowing over the Arabian Gulf, yielding estimated dust sedimentation rates of 0–8 mm yr−1. This is substantially higher, by several orders of magnitude, than dust fallout estimates in most seas of the world. The calculated fallout rates are in line with the results of existing field measurements.