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.