The 2012 Summer Games marked Sibusiso Matsenjwa's Olympic début. He was oldest competitor for Swaziland at the Games, aged 24. He qualified for the Olympics via a wildcard, as his best time, 21.29 seconds set at the 2011 World Championships in Athletics, was 0.64 seconds slower than the "B" qualifying standard for his event, the men's 200 metres. In an interview with the "Times of Swaziland" before competing Matsenjwa said that he was learning from training with other Olympic athletes and was confident of improving his performance. Matsenjwa competed in the men's 200 metres race in the third heat of the first round on 7 August, finishing sixth out of eight athletes with a time of 20.93 seconds, setting a new Swaziland national record. Overall he finished 40th out of 53 athletes, and was 0.21 seconds slower than the slowest qualifier for the semi-finals and, therefore, that was the end of his competition.