Teddy Williams and Cai Evans, named among the replacements for this fixture, are in line to win their first senior Wales caps on the weekend in the match that kicks off at 16h15 (SA time).
Jac Morgan, who starts at openside flanker, will captain the side for the second time. Dan Lydiate (blindside flanker) and Aaron Wainwright (No 8) join Morgan in the Wales back row.
Elliot Dee (hooker) starts his first match this August, with Corey Domachowski (loosehead prop) and Keiron Assiratti (tighthead prop) winning their second caps and completing the Wales front row.
Ben Carter and Will Rowlands pair up in the second row. Dan Biggar (flyhalf) is named in the starting XV after two appearances off the bench against England.
Mason Grady makes his first start this August, partnering Johnny Williams in the Wales midfield. Liam Williams is named at fullback for the second consecutive match. Rio Dyer completes the Wales starting line-up.
Among the replacements Tomos Williams and Max Llewellyn are alongside Evans as the backline cover.
Sam Parry, Nicky Smith and Henry Thomas are the Wales front row cover and Taine Basham, who was not a confirmed concussion following completion of all three stages of the head injury assessment (HIA) protocol, provides the back row cover.
Gatland said: “Preparations have gone well. We’re really pleased with the whole squad. We’re trying to build some depth within the team and there’s been a great atmosphere.
“In the first couple of games what was really pleasing for me was the physicality we brought and the way we defended. There are still things for us to work on in terms of being much more accurate. There’s been a lot of learning from that second England game and hopefully we put that into practice against South Africa. There’s another opportunity for this group of 23 players to put their hand up before we select the world cup squad.
“We’re expecting confidence and physicality from South Africa. They don’t make a lot of mistakes. It’s a very experienced team for them. But we’ve got a great chance to go out there in front of a home crowd and produce some of the good things that we did in both the games against England. We just need to make sure we play for 80 minutes and are accurate for 80 minutes.”
UPDATE: Injury concerns have forced Gatland to make a number of late changes to the team to face the Boks, with the British & Irish Lions backline trio of Dan Biggar, Liam Williams and Alex Cuthbert ruled out. They were replaced by Cai Evans (fullback), Tom Rogers (right wing) and Sam Costelow (flyhalf) in the starting team, with Louis Rees-Zammit named on the bench.
Wales team (updated): 15 Cai Evans, 14 Tom Rogers, 13 Mason Grady, 12 Johnny Williams, 11 Rio Dyer, 10 Sam Costelow, 9 Kieran Hardy, 8 Aaron Wainwright, 7 Jac Morgan (captain), 6 Dan Lydiate, 5 Will Rowlands, 4 Ben Carter, 3 Keiron Assiratti, 2 Elliot Dee, 1 Corey Domachowski. Replacements: 16 Sam Parry, 17 Nicky Smith, 18 Henry Thomas, 19 Teddy Williams, 20 Taine Basham, 21 Tomos Williams, 22 Max Llewellyn, 23 Louis Rees-Zammit.