At the 2012 Olympics in London, Boyle was fourth fastest in the heats of the 400m freestyle in a New Zealand record 4:03.63. In the final she finished 8th. In the 800m heats she swam 8:25.91, also a New Zealand record, qualifying fifth fastest for the final. In the final she swam another record of 8:22.72 to finish fourth, 2.40 seconds from the bronze medal which went to defending champion and world record holder Rebecca Adlington.