At the 2004 Summer Olympics in Athens, Hell shortened his program, swimming only in the 400 m freestyle. He finished first ahead of his teammate Christian Hein from the Olympic trials, in a FINA A-standard of 3:51.48. On the first morning of the Games, Hell placed eighteenth in the preliminaries. Swimming in heat four, he raced to fifth place by a 4.55-second margin behind winner and defending Olympic silver medalist Massimiliano Rosolino of Italy, outside his entry time of 3:52.06. He also teamed up with Jens Schreiber, Lars Conrad, and Christian Keller in the 4×200 m freestyle relay. Swimming the second leg, Hell recorded a split of 1:49.15, but the Germans pulled off again with a sixth-place effort, in a final time of 7:16.51.