Stuart Hayes (born 16 April 1979 in Isleworth, London) is an English triathlete. Hayes began his sports career as a swimmer at Hounslow Swimming Club but converted to triathlon at the age of 15; Hayes said he became "fed up of swimming up and down all day counting tiles". He is coached by his wife, Michelle Dillon. Hayes missed out on selection for the 2004 Summer Olympics in Athens, Greece, but finished the year ranked 3rd in the world. He failed to qualify for the 2008 Summer Olympics in Beijing, China, after suffering two punctures during the qualification event.