At the 2004 Summer Olympics in Athens, Han shortened his program, swimming only in the men's 200 m freestyle. He cleared a FINA B-standard entry time of 1:50.54 from the World Championships in Barcelona, Spain. He challenged seven other swimmers in heat five, including three-time Olympian Jacob Carstensen of Denmark. Han rounded out the field to last place by two hundredths of a second (0.02) behind Hungary's Tamás Szűcs, outside his entry time of 1:52.28. Han failed to advance into the semifinals, as he placed thirty-third overall in the preliminaries.