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.

In 2011, Hirai competed at the 2011 FINA World Junior Swimming Championships.

In the 2014, Hirai competed at the 2014 Pan Pacific Championships in the 100 meter butterfly, finishing 7th.

Later, Hirai went on to compete in the 2014 Asian Games, and winning the silver medal in the 200 meter butterfly.

In 2016, Hirai competed in the 2016 FINA Swimming World Cup, placing 5th in the 200 meter butterfly.