She learned to swim at the age of six and was training seriously two years later. In her biography "Against the Tide" published in 1984, Davies records that 'being accepted into Ray's Port of Plymouth squad was one of the many watershed points of my career' she goes on to describe how 'he corrected all her bad habits and developed me into a four-stroke swimmer. Ray laid the foundations of the medley swimmer that was to blossom later'. She set a record by swimming for the British national team at the age of only eleven. In 1976, at age thirteen, Davies was selected to represent Great Britain at the 1976 Summer Olympics in Montreal. The next year she won two bronze medals in the 1977 European Championships. The following year, at age fifteen, she won gold medals at the Commonwealth Games in the 200 and 400-metre individual medleys and also a silver and a bronze medal.