Hall was selected to represent Great Britain at the 2012 Summer Olympics in the women's triathlon alongside Helen Jenkins and Vicky Holland. Hall, who was ranked 148th in the world points list at the time of her selection, was chosen ahead five British athletes ranked in the world's top 100 because of her ability to perform a domestique role for Jenkins. In preparation for the triathlon, Hall trained in Bridgend for 10 days with Jenkins. The triathlon took place in Hyde Park with the swim being held in the Serpentine. The cycle involved athletes leaving the park via Queen Mother's Gate, travelling through Wellington Arch, down Constitution Hill and on to Birdcage Walk in front of Buckingham Palace before returning to the park to complete the event with a four lap run around the Serpentine. After leading the pack in the swimming leg and much of the cycling, Hall placed 33rd with a final time of 2:04:38 – she had the best swim relay of all.