Tom McWilliam competed in the Star class two-person keelboat at the 1992 Barcelona Olympic Games alongside Mark Mansfield, finishing 15th overall.

McWilliam and Mansfield were early selections identified in 1991 as having realistic medal-winning prospects, and they qualified for Barcelona with a third-place finish at the Star European Championships. Their regatta was described by team manager Michael Wallace as ‘frustrating’ – the light wind conditions that predominated in the Olympic regatta put them under particular pressure, as their outstanding strength was in heavy winds. McWilliam was one of the most experienced Irish Star class sailors of his era.