A Synthetic Aperture Radar (SAR) is an active microwave sensor, which provides radar images at high spatial resolution. SARs have been flying on several earth-orbiting satellites since the late 1970s, thereby providing a great deal of highresolution radar imagery of coastal regions. We provide an overview of several oceanic and atmospheric processes and phenomena in the marine coastal environment that can be seen on SAR imagery. Among them are wind and wave fields, oceanic internal waves, marine surface films and oil pollution, sea bottom topography, ships (vessels), and heavy rain. We illustrate the wealth of information that can be inferred from radar imagery with spatial resolutions reaching a few decimetres and demonstrate the benefit of SAR data to scientists, coastal managers, agencies, and public or commercial bodies.