In high school, she swam for the Ipswich Swimming Club and competed on a national level, but eventually burned out at age 17.

She read politics and law at the University of Birmingham, where she joined the swim team, which had a more social approach to the sport.

[7] The next year she reduced her work hours with her law firm to devote more time to training and to try to make it as a professional triathlete.

At the Ironman World Championships that year she missed a podium spot by taking 4th at the race, just behind Leanda Cave.

A month later Joyce won the 2011 ITU Long Distance Triathlon World Championships over second place Cave.

[10] That same year, coming into the 2013 Ironman World Championships, Joyce was considered to be among the favorites to win the event.