At the 1978 Commonwealth Games in Edmonton, Alberta, Canada, Wickham won both the 400 m and 800 m freestyle. That same year, she set world records in both events, and won both the 400 m and 800 m freestyle at the 1978 Berlin World Championships, setting a world 400 m record of 4.06.28, which stood as the Championship record until 2007. Both world records stood until 1987, long after her retirement.