Kim qualified for the women's 400 m individual medley at the 2012 Summer Olympics in London, by clearing a FINA B-standard entry time of 4:46.56 from the Dong-A Swimming Championships in Ulsan. She topped the second heat by nearly two seconds ahead of seven other swimmers, including former bronze medalists Sara Nordenstam of Norway and four-time Olympian Georgina Bardach of Argentina, breaking her personal best of 4:43.99. Kim's overwhelming triumph was not enough to advance her into the final, as she placed seventeenth overall in the preliminary heats. She plans on competing in the 2020 Tokyo Olympics.