South Africa play their hosts in three T20 matches between August 10th and 16th before a three-game ODI series from August 19th to 24th.
Subrayen, 31, recently made his test debut in Zimbabwe, as did Brevis, 22, and Pretorius, 19. All three players have been included in both limited-overs squads.
Having rested several regulars for the tri-series tournament in Zimbabwe this month, which also includes New Zealand, South Africa have recalled Aiden Markram, Kagiso Rabada, Ryan Rickelton and Tristan Stubbs.
Key all-rounder Marco Jansen misses out on the tour through injury.
Markram will captain the T20 side, and Temba Bavuma will lead the ODI team.
South Africa T20 squad
Aiden Markram (captain), Corbin Bosch, Dewald Brevis, Nandre Burger, George Linde, Kwena Maphaka, Senuran Muthusamy, Lungi Ngidi, Nqaba Peter, Lhuan-dre Pretorius, Kagiso Rabada, Ryan Rickelton, Tristan Stubbs, Prenelan Subrayen and Rassie van der Dussen.
South Africa ODI squad
Temba Bavuma (captain), Corbin Bosch, Matthew Breetzke, Dewald Brevis, Nandre Burger, Tony de Zorzi, Aiden Markram, Senuran Muthusamy, Keshav Maharaj, Wiaan Mulder, Lungi Ngidi, Lhuan-dre Pretorius, Kagiso Rabada, Ryan Rickelton, Tristan Stubbs and Prenelan Subrayen.