Ippei Watanabe (渡辺 一平, Watanabe Ippei, born 18 March 1997) is a Japanese swimmer and former world record holder in the 200 metre breaststroke.

He competed in the men's 100 metre breaststroke event at the 2016 Summer Olympics.

[1] On 9 August 2016, Watanabe broke the Olympic record for the men's 200 metre breaststroke event at the 2016 Summer Olympics during the semi-final.

At the Kosuke Kitajima Cup in Tokyo he broke the long course 200 metre breaststroke world record in a time of 2:06.67.

This Japanese swimming biography is a stub.