Yasuo Watani (born in 1960) is a Japanese chromatic harmonica player. He was born in Kyoto, Japan and had his first harmonica lessons with Tadao Kobayashi in 1966.

After graduating from Doshisha University (Faculty of Commerce) in 1984 with a degree in Economics, he studied the chromatic harmonica with Helmuth Herold at the Hohner Conservatory Trossingen in Germany from 1984 to 1988. He also learned the harmonica from the British harmonica virtuoso Tommy Reilly.

First prize and special prize at the International Harmonica Competition (Netherlands) 1988, first prize at the World Harmonica Championships  (Germany)1989.

He was invited to stay on as a Lecturer at the Hohner Conservatory and taught from 1988 to 2002.

Since 2005, he is a Music Lecturer for harmonica at Senzoku-Gakuen College of Music, Japan. Performs with orchestras and gives recitals all over the world. His students have won first prize in many international competitions.

He has been invited to judge at many harmonica competitions and festivals, including World Harmonica Festival and Asia Pacific Harmonica Festival.