Abba qualified for the men's 100 m freestyle at the 2004 Summer Olympics in Athens, by receiving a Universality place from FINA, in an entry time of 58.24. He set an Iraqi record of 56.81 to lead the first heat against six other swimmers, including 34-year-old Mumtaz Ahmed of Pakistan. Abbas failed to advance into the semifinals, as he placed sixty-third overall out of 71 swimmers in the preliminaries.