The 29-year-old won in a time of 5.58.53, becoming the first women to complete the Durban to Pietermaritzburg route in under six hours.
Steyn was the 17th person over the line at the Scottsville Racecourse.
The men's race was won by Edward Mothibi.
Bulwer's Bongmusa Mthembu came home second.
You can share your 2019 Comrades Marathon photos with us. Tag @ECR_Newswatch on Twitter.
Our Producer recently lost his mom and following her death, he needed to...East Coast Drive with Bongani and Mags 9 hours ago
A group of beachgoers banded together to perform a massive rescue effort...Stacey Norman on East Coast Radio 15 hours ago