Coates finished third in the 200-metre freestyle at the 2016 British National Championships. As a result, she was selected as part of the Great Britain team for the 2016 Summer Olympics in Rio de Janeiro, Brazil, where she will compete in the 4 × 200-metre freestyle relay with Jazmin Carlin, Ellie Faulkner and Camilla Hattersley. At 17-years-old Coates is the youngest member of the Great Britain swimming team at the Games.