Four years later, Choi qualified for two swimming events at the 2012 Summer Olympics in London by clearing FINA A-standard entry times of 2:13.00 (200 m individual medley) and 2:08.81 (200 m butterfly) from the FINA World Championships in Shanghai, China. In the 200 m individual medley, Choi finished heat four in sixth place by 0.19 of a second behind Great Britain's Sophie Allen, lowering her Olympic time to 2:14.91. She placed twenty-fourth in the preliminary heats, and did not advance further into the semifinals. Unlike her previous Olympics, Choi registered a tenth fastest time of 2:08.45 in the 200 m butterfly to secure her spot for the semifinals on the morning's preliminary heats. Choi failed to qualify for the final, as she finished the semifinal run with a third-slowest time of 2:08.32.