Motivated by the abundance of low clouds in the subtropics, where the easterly trade winds prevail, we study the role of shallow convection in the momentum budget of the trades. To this end, we use ICON-LEM hindcasts run over the North Atlantic for twelve days corresponding to the NARVAL1 (winter) and NARVAL2 (summer) flight campaigns. The simulation protocol consists of several nested domains, and we focus on the inner domains (≈100x100 km2) that have been run at resolutions of 150–600 m, which are subjected to a realistically varying flow that has developed in the outer domain. Combined, the resolved advection and the subgrid stresses decelerate the easterly flow from the surface up to about 2 km in winter and 1 km in summer, a result that is insensitive to horizontal resolution. The unresolved processes are strongest near surface and are well captured by traditional K-diffusion theory, but convective-scale motions that are not considered in K-diffusion theory contribute the most in the upper part of mixed layer and are strongest just below cloud base. The results point out that convection in the mixed-layer — the roots of trade-wind cumuli and subcloud layer circulations — play an important role in slowing down easterly flow below cloud base (but little in the cloud layer itself), which helps make the zonal wind jet more distinct. Most of the friction within the clouds and near the wind jet stems from smaller-scale turbulence stresses.