Nearshore wind speeds retrieved by WindSat are validated by a comparison with the moored buoy observations near the U.S.west and east coasts.A 30 min and 25 km collection window is used for the Wind Sat wind data and buoy measurements from January 2004 to December 2014.Comparisons show that the overall root-mean-square error is better than 1.44 m/s near the U.S.coasts,and the result for the east coast is better than that for the west coast.The retrieval accuracy of the descending portions is slightly better than that of the ascending portions.Most buoy-to-buoy variations are not significantly correlated with the coastal topography,the longitude and the distance from the shore or satellite-buoy separation distance.In addition,comparisons between a polarimetric microwave radiometer and a microwave scatterometer are accomplished with the nearshore buoy observations from 2007 to 2008.The Wind Sat-derived winds tend to be lower than the buoy observations near the U.S.coasts.In contrast,the Quik SCAT-derived winds tend to be higher than the buoy observations.Overall,the retrieval accuracy of Wind Sat is slightly better than that of Quik SCAT,and these satellite-derived winds are sufficiently accurate for scientific studies. Nearshore wind speeds retrieved by WindSat are validated by a comparison with the moored buoy observations near the USwest and east coasts.A 30 min and 25 km collection window is used for the Wind Sat wind data and buoy measurements from January 2004 to December 2014. Comparisons show that the overall root-mean-square error is better than 1.44 m / s near the UScoasts, and the result for the east coast is better than that for the west coast. The retrieval accuracy of the descending portions is slightly better than that of the ascending portions. Master buoy-to-buoy variations are not significantly correlated with the coastal topography, the longitude and the distance from the shore or satellite-buoy separation distance. In addition, comparisons between a polarimetric microwave radiometer and a microwave scatterometer are accomplished with the nearshore buoy observations from 2007 to 2008. Wind Sat-derived winds tend to be lower than the buoy observations near the US coast. In contrast, the Quik SCAT-derived winds tend to be higher than the buoy observations. Overall, the retrieval accuracy of Wind Sat is slightly better than that of Quik SCAT, and these satellite-derived winds are rendered accurate for scientific studies.