Margaret Sills comes from a swimming background but took up running in her early 30s with a debut marathon in 1982 in London. Triathlon caught her eye in 1983 and she has competed in triathlons ever since. She qualified for the GB Age Group triathlon team for the first time in 1995 and has raced standard, middle and long distance World and European championships in GB strip many times since then. She has raced several full and half Ironman triathlons, qualifying for the World Ironman championships in Kona (Hawaii) in 2004, subsequently also racing 70.3 World Championships, for example in the USA (4th) and South Africa (7th). In 2018 she won the 65-69 age group at the European Middle Distance championships in Ibiza. In 2017 Margaret completed the 3 ascents and descents of Mount Ventoux, thus joining the Cinglé du Ventoux club.