As a schoolgirl, Susan Roberts was active in field hockey, tennis, lacrosse, and badminton, winning a Transvaal provincial junior title in the latter sport. It was swimming, however, where she excelled the most and she was selected to represent South Africa at the 1956 Summer Olympics after setting a national record in the 880 yards freestyle event while winning the South African title. There she was a member of the 4x100 metres freestyle relay squad (with Moira Abernethy and Jeanette and Natalie Myburgh) that took the bronze medal. She also competed individually in the 100 and 400 m events, but did not reach the final of either. Her other major tournament was the 1958 British Empire and Commonwealth Games, where she finished fourth in the 4×110 yards freestyle relay (with Natalie Myburgh and the non-Olympians M.M. Hogg and S.G. Wetton) and fifth in the 4×110 yards medley relay (with Wetton, Natalie Myburgh and the non-Olympian J. Rocchi). Roberts was also eliminated in the heats of the 110 yards freestyle, the 440 yards freestyle, and the 110 yards backstroke. Between 1955 and 1958 she earned numerous Transvaal provincial and South African titles and set several records across various individual disciplines. She entered Cape Town University in 1956 to earn a social science degree and was active on the school’s swimming and badminton teams.