Satellite radar altimeter measurements of sea surface height (SSH), significant wave height, and wind speed have many potential applications in coastal zones, despite the common perception that altimetry does not “work” near the coast. The altimeter's primary measurement, the radar travel time from the spacecraft to the sea surface, is reliable seaward of 10 kilometers from the coast, and sometimes closer. The Ocean Surface Topography Mission altimeter on Jason 2, launched on 20 June 2008, has a new tracking mode that may recover more data in the coastal zone, and the launch of CryoSat 2 next year will demonstrate the coastal capabilities of a delay-Doppler altimeter. Turning radar travel time into accurate SSH requires ancillary water vapor radiometer measurements that may become unreliable within 50 kilometers of the coast. Interpretation of SSH data in the coastal zone is complicated where tides and other SSH corrections may change abruptly over shallow coastal shelves or near land.