Kammala jumla mai zuwa: Shekaru huɗu bayan haka, Choi ya cancanci shiga wasannin ninkaya guda biyu a Wasannin Olympics na bazara na 2012 a London ta hanyar share FINA A-daidaitaccen shigarwar lokaci na 2: 13.00 (m 200 na mutum) da 2:08.81 (m 200 na malam buɗe ido) daga Gasar Cin Kofin Duniya ta FINA a Shanghai, China. A cikin tseren tseren mutum 200 m, Choi ya gama zagaye na huɗu a matsayi na shida ta hanyar 0.19 na na biyu a bayan Sophie Allen na Burtaniya, yana rage lokacin wasanta na Olympics zuwa 2:14.91. Ta sanya na ashirin da huɗu a cikin zafin jiki na farko, kuma ba ta ci gaba da zuwa wasan kusa da na karshe ba. Ba kamar wasannin Olympics da ta gabata ba, Choi ta yi rikodin sa'a ta goma mafi sauri na 2:08.45 a cikin
200 m butterfly don tabbatar da matsayinta na wasan kusa da na karshe a zagayen farko na safiyar yau. Choi ta kasa cancanta zuwa wasan karshe, yayin da ta gama zagaye na kusa da na karshe tare da na uku mafi jinkirin lokaci na 2:08.32.