Chantal Gibney competed in four freestyle events at the 2000 Sydney Olympic Games – the 50 metres, 100 metres, 200 metres and 400 metres – making her one of the most active members of the entire Irish team at those Games.

From Dublin, Gibney began swimming at the age of six with Trojan Swim Club. She qualified for Sydney after reaching the semi-finals of the 200 metres freestyle at the 2000 European Championships in Helsinki, where she finished 10th with a personal best of 2:02.83 – a FINA A standard. She also broke Michelle Smith’s longstanding Irish 50 metres freestyle record at the Ulster Open in Belfast in 1999.

In early 2000 she relocated to Fort Lauderdale, Florida, training full-time with the Blue Wave Swim Team under coach Peter Banks in preparation for Sydney. Her best Olympic result came in the 200 metres freestyle where she finished 28th. She subsequently attended the University of Florida, earning fifteen All-American honours under coach Gregg Troy. She holds Irish national records in the 200 metres and 400 metres freestyle.