A numerical procedure for simulating electromagnetic scattering from the sea surface is presented. The simulation scheme is based on a physical model of the sea surface; the surface is generated starting from its two-dimensional directional spectrum. The scattered electromagnetic field is evaluated by resorting to a two-scale electromagnetic model. Physical parameters can be taken into account in simulations, as for instance, the local wind velocity direction and strength. The procedure is applied to the case of real aperture radar systems operating at low and intermediate incidence angles. In order to demonstrate the effectiveness of the simulation technique proposed, numerical results are presented and compared with experimental data available in the literature.