The champion breaststroker - Australian swimming's first four-time Olympian - announced the end of a 13-year international career on Friday.
The 27-year-old claimed her ninth Olympic medal in London, equalling Ian Thorpe's record for most won by an Australian.
At 15, she became Australian swimming's youngest Olympic medallist by winning two silvers at the Sydney Games.
Her physique was a talking point at the London Games, sparking speculation it was her farewell event.