At the 2004 Summer Olympics in Athens, Singleton qualified for Team GB in the women's half-lightweight class (52 kg), by placing fifth at the World Championships in Osaka, Japan, and securing a place with her performance from the British judo trials in Wolverhampton. Singleton got off to a firm start with convincing victories over Brazil's Fabiane Hukuda and Venezuela's Flor Velázquez in the prelims, before she conceded with a shido penalty and then succumbed to an ippon hold from Japan's Yuki Yokosawa during their quarterfinal match. In the repechage round, Singleton edged past North Korea's Ri Sang-Sim with an uchi mata makikomi (inner thigh wraparound) hold to permit herself a chance for an Olympic medal, but her rigid form was not enough to combat Belgium's Ilse Heylen in their subsequent match, relegating Singleton into the seventh position.