Michael Williamson represented Ireland in the men’s 200 metres breaststroke at the 2004 Athens Olympic Games, finishing 6th in his heat in 2:15.75 and 22nd overall – not advancing to the semi-finals.

He qualified for the Games by achieving the FINA A standard of 2:14.18 at the British Olympic trials in Sheffield, and was drawn in a formidable heat alongside top medal favourites Brendan Hansen of the United States and Dániel Gyurta of Hungary.

He had previously won bronze in the 200 metres breaststroke at the 2003 Summer Universiade in Daegu, South Korea, with a time of 2:15.52 – one of the best results by an Irish swimmer at that competition.

He retired from competitive swimming three months after the Athens Games.