Han qualified for the women's 800 m freestyle at the 2012 Summer Olympics in London, by eclipsing a FINA B-standard entry time of 8:50.16 from the Dong-A Swimming Championships in Ulsan. She challenged seven other swimmers on the second heat, including two-time Olympians Lynette Lim of Singapore, Khoo Cai Lin of Malaysia, and Nina Dittrich of Austria. She rounded out the field to last place by five seconds behind Lim in 8:57.26. Han failed to qualify for the final, as she placed thirty-second overall in the preliminary heats.