Masempe Theko was participating in her first Olympic Games at the age of 25. She qualified after receiving a universality place awarded by FINA because her best time of 49.75 seconds in the women's 50 metre freestyle, was 23.99 seconds slower than the "B" standard qualifying time. Theko said that it was an "honour" that she was chosen to respent her country: "I don't know how to explain it, but in my head it really plays out big. I'm looking forward to the event, being in London and meeting new friends and acquaintances." She was drawn in the first heat of the women's 50 metre freestyle on 3 August, finishing third (and last), with a time of 42.35 seconds. Theko reacted over a second after the gun fired to signal the start of the heat, although she improved her personal best time by over seven seconds. She finished 73rd (and last) of all swimmers overall, and did not advance to the semi-finals because her time was 17.07 seconds slower than the slowest athlete who progressed to the later stages.