Van Zyl made her marathon debut at the 2012 London Marathon and her time of 2:33:41 brought her 18th place and spot on the South African team for the 2012 Summer Olympics in London. However, she failed to finish at the women's Olympic marathon on her return to the city in August. Van Zyl began 2013 with a four-win streak in South African half marathons. She placed tenth at the 2013 London Marathon, completing the distance in a time of 2:31:26 hours. She ran her best time of 2:28:40 at the 2021 Xiamen Tuscany Camp Elite Marathon in Siena, Italy.