This paper explores the potential of high-resolution spaceborne Synthetic Aperture Radar data for mapping intertidal coastal areas as a complement of high-resolution optical imagery (e.g. SPOT, Formosat-2). Classification algorithms based on optical imagery alone fail to accurately discriminate a series of relevant habitats, in particular seabeds of benthic fauna (oysters), low-density Zostera noltii seabeds and salt-marsh vegetation species. Firstly, the paper addresses the benefits from TerraSAR-X data by investigating SAR signatures over intertidal wetlands which have been poorly described in the literature. Secondly, a supervised classification algorithm is run based on the fused SAR-optical bands. A statement of the mapping performance is finally carried out using field observations.