At the London Olympics, Symmonds was one of the two time qualifiers for the final of the 800m. He placed fifth in the final with a new personal best of 1:42.95; David Rudisha placed first in the world record time of 1:40.91., with Nijel Amos of Botswana second, Timothy Kitum of Kenya third, and Symmonds' teammate Duane Solomon fourth.