Olivia Mathias (born 12 October 1998) is a Welsh professional triathlete.

[1] She competed at the 2022 Commonwealth Games, in Mixed relay, winning a silver medal.

[2][3][4] She competed at the 2018 Commonwealth Games.

In August 2019, she won silver in the women's U23 race at the Triathlon World Championships in Lausanne, Switzerland.

[5] She competed at the 2022 Europe Triathlon Cup Kitzbühel, winning a gold medal.