Kenta Hirai (born May 7, 1994) is a Japanese competitive swimmer who won the silver medal in the 200 meter butterfly at the 2014 Asian Games. He also won the silver medal in the 200 meter butterfly at the 2013 Summer Universiade, and the gold medal in the same event at the 2011 FINA World Junior Swimming Championships. He also has an additional 2 silver medals, both won at the 2001 Junior World Championships, in the 100 meter butterfly and the 4x100 meter medley relay. He has won a total of 5 international medals, with 1 gold and 4 silver.