There were fears the Springboks, who aren’t participating in this year’s tournament due to the affects of COVID-19, would link up with northern hemisphere nations.
The tournament is currently being played in Australia but as a Tri-Nations involving Australia, New Zealand and Argentina.
However, SANZAAR announced on Wednesday South Africa were on board for 2021 and beyond.
The championship will be restructured to include a 12-match format with teams playing each other on a home and away basis.
In 2019, when the competition was won by South Africa, teams only played each other once with the tournament shortened due to the World Cup.
SANZAAR boss Andy Marinos said more announcements would be forthcoming as more plans fell into place.
“This is the first of a number of announcements that will be made over the coming weeks and months as we continue to plan into 2021 and beyond,” he said.
“The disruption during 2020 has been significant, however, despite the numerous setbacks and the inherent complexity of our vast geographical expanse, we have managed to keep the game alive and look forward to the remainder of the revised Tri-Nations to bring the curtain down on the 2020 season.”