Simon had a successful amateur career. She was the youngest player to win the ladies’ South African Amateur Stroke Play and Match Play double and the first player in 101 years to win the Ladies South African Open title three times. She represented her country in the mainly professional Women's World Cup of Golf three times while still an amateur. Simon turned professional the day after her eighteenth birthday. She won the 2007 Catalonia Ladies Masters, which was her third event as a professional. She became the youngest ever professional winner on the Ladies European Tour (South Korea's Amy Yang won the 2006 ANZ Ladies Masters at a younger age as an amateur).