Keio Plaza Hotel is an upscale hotel in the Nishi-Shinjuku district in Shinjuku, Tokyo, Japan and the name of a chain of hotels.
Keio Plaza Hotel was the first skyscraper built in Nishi-Shinjuku and the first high-rise hotel in Japan. The hotel consists of two towers. The first tower is 178 metres tall and was completed on June 1971. The second tower is 138 metres tall and construction was finished in November 1980. The 1,450-room hotel is a re-development project on the site where a water purification plant (Yodobashi Purification Plant) formerly existed.