Deposition to the sea surface is a major loss pathway for highly soluble atmospheric trace gases. These fluxes are important to biogeochemical cycles, climate, and air quality. Here we report measurements of air–sea fluxes of sulfur dioxide, sensible heat, and momentum to coastal waters. Transfer velocities derived from the data show a dependence on molecular diffusivity, demonstrating the importance of diffusion in the interfacial layer on the atmospheric side of the air–sea interface.