The Comrades Marathon Association offered a further 1500 spots on Thursday morning, saying the extra runners could be accommodated without compromising safety or race experience. But the extra places were gone by late on Thursday afternoon.
"All entries received until 4.30pm . will be accepted and are currently being processed, including postal entries postmarked September 21 or earlier," the association's race director, Rowyn James, said. "All entries received after this time will be rejected.
"The pace at which entries have been snapped up has been phenomenal.
"The safety and wellbeing of our runners, and the integrity of the event, remain the top priority."