At the 2004 Summer Olympics in Athens, Felgueiras qualified again for the 200 m butterfly by eclipsing a FINA B-cut of 2:13.08 from the European Championships in Madrid. She challenged seven other swimmers on the same heat as Sydney, including top medal favorite Éva Risztov of Hungary. She raced to sixth place by 0.54 of a second behind Risztov's teammate Beatrix Boulsevicz, matching her personal best and entry time of 2:13.08. Felgueiras failed to advance into the semifinals, as she placed twentieth overall in the preliminaries.