Caoili began playing chess at the age of six. At the age of 14, she scored 5.5/9 in the strong Conca Della Presolana tournament in Italy in 2001. At one point during 2002, she achieved a FIDE rating in excess of 2300, but this has been in decline since she scaled down her chess activities to concentrate on her studies. Nevertheless, she remains one of Australia's leading woman players and played top board for the national team at the Dresden Olympiad in 2008. In 2009 Caoili won the London Chess Classic Women's Invitational tournament with 8/9, two points ahead of the runner-up.