The two players, alongside Noam Davey, visited the country in June as part of their continued personal development.
The trip to East London formed part of an exchange programme with the South African Rugby Union (SARU), the north Wales Academy boys spending a month in the town affectionately known as Buffalo City.
The three players trained with the SARU Border Academy while as part of the programme, players from South Africa will come to north Wales to train and play into the future.
Scrum half Bagshaw and backrower Parry will now push for a place in the RGC 1404 side which will compete in the SWALEC Championship this season.
"The South Africa trip was a really good experience for the boys and great for the set-up here in north Wales," said Horsman.
"One thing we are really keen on is not just developing rugby players but also developing people and opening their horizons as much as possible.
"That's vital and can add massive amounts of value to both individual players and the team.
"Hopefully they can push on now and challenge for a place in the starting 15 for this season."
Marc Roberts, WRU Performance Manager for north Wales, commented: "This was a fantastic opportunity for our young players to develop their rugby skills in a totally different environment.
"It also gave them some valuable life experience. Our ambition within the Academy is to develop good people as well as good rugby players and with schemes like this, we can widen young player's perspectives."
After jetting out to South Africa, the three RGC players took part in pre-season training which included fitness as well as rugby specific training drills.
Rupert Moon, RGC 1404 General Manager, said: "This partnership is vital both in terms of giving young RGC 1404 players the chance to experience rugby abroad and also vice versa for the South African players.
"It also means that going into the start of our first season in the SWALEC Championship, the players who went will be pushing for a first team spot.
"This is a partnership we are looking to continue with South African players coming over to train with us into the future."
Richard De Jager, International Exchange Co-ordinator for the SARU, said: "These trips are a good cultural and learning experience for the boys from both countries.
"Our boys go and train in ice and snow whereas the Welsh boys get to experience the high heat and temperatures of our country.
"From our perspective it opens our boys up to a different standard of rugby which can only benefit them.
"In terms of the Welsh boys who came over, they joined in with pre-season fitness training and their attitude was exceptional. They put in the hard work and got stuck in."