William "Bill" Mahony (born September 16, 1949 in New Westminster, British Columbia) is a former Breaststroke swimmer from Canada, who's eight years of National Records and competing Internationally for Canada began in 1966 at the Commonwealth Games in Jamaica, with a Bronze in the 220 yd breaststroke.
Mahony swam in two Summer Olympics, at Mexico City(1968), and later in Munich (1972) on the Bronze Medal winning 4×100 m medley relay, alongside Erik Fish, Bruce Robertson, and Robert Kasting. At the 1970 Commonwealth Games in Edinburgh he was a triple Gold Medal winner, in the 100 m and 200 m Breaststroke, and the 4×100 m Medley. In his last swim, at his third consecutive Commonwealth Games (New Zealand,1974), he helped to win Gold in the Medley Relay.
From 1977 to 1987 he developed the Adapted Aquatics program at Variety's Treatment Centre in Surrey,BC,and helped to form the BC Branch of the Cerebral Palsy Sports Association. Later, while coaching Parapalegic and Blind swimmers, he was chosen to Coach the Canadian swimmers at the 1980 Olympics for the Disabled in Holland.
He was awarded Athlete of the Year in New Westminster, and inducted into the BC Swimming, Canadian Swimming, and BC Sports Halls of Fame.