Also on board the plane are two players returning from injury in lock Alex Ainley and flanker John Hardie.
Ainley broke his jaw in a club match about six weeks ago but is expected to be right for this week's match against the Lions.
He is yet to take the field for the Highlanders this season but, with the Highlanders only taking three locks on the trip, Ainley is expected to get a run.
Tom Franklin and Mark Reddish are the other locks heading away. Joe Wheeler is out for the season with a knee injury.
Wider training squad member Joe Latta, who has played in the past two games, has stayed in New Zealand.
Hardie picked up a nasty ankle dislocation in mid-March against the Waratahs and has made a slow return to full fitness. He is, like Ainley, expected to be available for the match against the Lions.
Shane Christie's frustrating season continues. He tore his hamstring in the last pre-season game in February and, coming back in March, damaged it in the warm-up against the Waratahs.
He was scheduled to play club rugby last weekend but injured the hamstring again on Thursday and it is unclear when he will be sighted this season.
When Hardie and Christie were on the sidelines, Otago flanker James Lentjes was called into the squad and played four games. But he has been left at home and Dan Pryor and Hardie look set to be the options for the openside flanking role. Prop Ross Geldenhuys is over his broken thumb and is on the tour.
The players left behind from the full squad are props Pingi Tala'apitaga and Daniel Lienert-Brown, utility back Trent Renata and fullback Kurt Baker.
Winger Ryan Tongia has travelled with the team after being out with injury for the past month. Lienert-Brown has been getting over a knee injury suffered in the win against the Crusaders.
Halaholo comes into the side as wider squad training member Sam Anderson-Heather is out with a shoulder injury.
It is a tough break for Anderson-Heather, who made his Highlanders debut last year but has been hampered by injury over the past couple of seasons.
Three hookers have been taken as both Liam Coltman and Ash Dixon have got through plenty of work so far this season.
Only two halfbacks - Aaron Smith and Fumiaki Tanaka - have travelled to South Africa.
The Highlanders are heading to Johannesburg via Sydney. They will spend the week in Johannesburg before transferring to Bloemfontein the following week.
The Highlanders will then head to Perth to take on the Force on May 23.
The final three games of the season are against New Zealand sides in Invercargill, Napier and Auckland respectively.
Highlanders squad
Liam Coltman, Ash Dixon, Dillan Halaholo, Brendon Edmonds, Josh Hohneck, Kane Hames, Ross Geldenhuys, Alex Ainley, Mark Reddish, Tom Franklin, Dan Pryor, Elliot Dixon, Gareth Evans, John Hardie, Nasi Manu, Fumiaki Tanaka, Aaron Smith, Lima Sopoaga, Marty Banks, Shaun Treeby, Richard Buckman, Jason Emery, Malakai Fekitoa, Ryan Tongia, Patrick Osborne, Waisake Naholo, Ben Smith.
