He went to two Olympics in 1964 and 1968 competing in the men's road race and team time trial. In the men's road race, he finished 61st in 1964[2] and 52nd in 1968.[3][4]
His brother Richie Thomson was also a New Zealand representative cyclist competing at two Commonwealth Games and the 1968 Olympic Games.
Des Thomson also won the Australian Road title. He rode for Queensland having moved to the Gold Coast and joining Nerang – Gold Coast cycling club.