Niamh Coyne (born 22 June 2001) is an Irish swimmer. She competed in the women's 50 metre breaststroke at the 2019 World Aquatics Championships held in Gwangju, South Korea and she did not advance to compete in the semi-finals. At the 2022 U.S. Open Swimming Championships, held in Greensboro, United States, Coyne won the b-final of the 100 metre breaststroke with a time of 1:09.49.