The azimuthal resolution of the Synthetic Aperture Radar (SAR) when imaging the permanently moving ocean surface is determined by the coherence time of the imaged scene. The scene coherence time thus constitutes one of the major parameters in SAR imagery of the ocean. The present study shows how the direct estimate of this parameter under the actual experimental conditions can be performed using a two-antenna interferometric SAR. The present results arc in agreement with earlier estimates.