The final, which takes place at 03:41 (SA time) on Friday, will see Schoenmaker start as comfortably the fastest qualifer from the semi-finals while Corbett qualified 4th fastest.
Schoenmaker and Corbett are training partners at Tuks in Pretoria.
While all eyes are on Schoenmaker and her efforts to bag a first gold medal for South Africa in Tokyo, it was Corbett up first on Thursday as she finished strong in her semi-final to win in a time of 2:22.08 with America’s Lilly King (2:22.27) second.
Schoenmaker, who had set a new Olympic record in the heats on Wednesday, then obliterated the field once more in her semi-final, coming home first in 2:19.33.
Schoenmaker, who is competing in her first Olympic Games, claimed the country’s first medal on Tuesday as she won silver in the women’s 100m breaststroke.
She is the overwhelming favourite to win on Friday.
South African teenager Matthew Sates, meanwhile, finished 8th in his 200m individual medley semi-final, failing to qualify for the final.