Dee ihe na-aga n'ihu maka paragraf a - Afọ anọ ka e mesịrị, Choi ruru eru maka ihe omume igwu mmiri abụọ na 2012 Summer Olympics na London site na imebi oge ntinye FINA A-ọkọlọtọ nke 2:13.00 (200 m onye medley) na 2:08.81 (200 m butterfly) site na FINA World Championships na Shanghai, China. Na 200 m onye medley, Choi kwụsịrị okpomọkụ anọ na nke isii site na 0.19 nke abụọ n'azụ Great Britain Sophie Allen, na-agbadata oge Olympic ya na 2:14.91. O tinyere nke iri abụọ na anọ na ọkụ ọkụ, ma ghara ịga n'ihu na ọkara ikpeazu. N'adịghị ka asọmpi Olympics ya ndị gara aga, Choi debere oge nke iri kachasị ọsọ nke 2:08.45 na 200 m butterfly
iji nweta ọnọdụ ya maka ọkara-ikpeazụ na ụtụtụ a prelims. Choi enweghị ike iru eru maka ikpeazu, ebe ọ kwụsịrị ịgba ọsọ nke ọkara ikpeazu na oge nke atọ kachasị nwayọ nke 2:08.32.