This study investigates the land subsidence in Miyagi Coast caused by The Great East Japan Earthquake of 2011 by analyzing water level measurement and tidal data. The continuous water level measurement data at Kobama, Nobiru, Onagawa, and Fukuchi were compared to the tidal level. It was found that before the earthquake, the recorded water level coincide well with the tidal level. The land subsidence caused vertical dislocation of the water level measurement device. Therefore,the measured water level elevation deviates from the astronomical tide. The land subsidence at each location was estimated based on this deviation. The estimated subsidence from the water level analysis at each location correlates well with the reported subsidence by the Geospatial Authority of Japan (GSI).