<p>Aerosols substantially influence the climate by modifying Earth’s radiative balance and marine biogeochemical cycles. However, accurate quantification of aerosol deposition onto ocean surfaces remains challenging due to the limited direct observations over oceanic regions. Here, to address this observational gap, we use the cosmogenic radionuclide beryllium-7, measured simultaneously in the atmosphere and seawater. Beryllium-7 is naturally produced in the atmosphere and rapidly attaches to submicrometre aerosol particles before being deposited onto the ocean surface through wet and dry processes, making it a direct tracer for quantifying aerosol deposition. We combine previous measurements from cruises in the North Pacific, equatorial Pacific, North Atlantic and Arctic oceans with measurements from the South Pacific, Indian and Southern oceans to derive a revised aerosol deposition parameterization across the global ocean. Compared with the parameterizations used in the GEOS-Chem chemical transport model, we find that aerosol deposition rates over the global ocean have been underestimated by 39 ± 23%, consequently overestimating aerosol lifetimes over the oceans by an average of 69 ± 92%. Our observationally constrained results suggest that aerosol processes are more dynamic than previously estimated, with important implications for our understanding of aerosol-driven climate effects and marine biogeochemical processes globally.</p>