A British national, Stanley was born in France, and also raised in Canada and Australia.
[2] In November 2022, he finished in sixth place in the U23 World Championships in Abu Dhabi.
[5] Stapley made his World Triathlon Championship Series debut in Sunderland in July 2023.
[9] In March 2024, he finished sixth in the World Triathlon Cup event in Hong Kong.
[11] From 2021, he was based in Leeds with his girlfriend, fellow triathlete, Kate Waugh.