In a widely expected move, a Special General Meeting of the South African Rugby Union (SA Rugby) decided in favour of entering the Bulls, Lions, Sharks and Stormers into an expanded PRO14, and effectively ending franchise competition against sides from Australia, New Zealand and Argentina.
The lucrative European television market, and more favourable time zones and travel logistics, are behind the move, with the Cheetahs and Southern Kings having played in the PRO14 since 2017.
The Cheetahs and Kings will be replaced by the new quartet, with the former possibly playing in a revamped SANZAAR Super Series, the details of which have yet to be announced, if costs can be kept neutral.
"Our members are excited about the prospect of closer alignment with the PRO Rugby Championship and seeking a northern hemisphere future, but we would not have been taking this decision but for actions elsewhere," SA Rugby chief executive Jourie Roux said in a statement.
His comments come after the New Zealand Rugby Union unilaterally decided to proceed with a domestic or trans-Tasman competition in the future that effectively brought an end to Super Rugby in its current format.
SA Rugby will now accelerate preliminary conversations with the organisers of PRO14 on their representation in the competition, which is a joint venture between the rugby unions of Ireland, Wales, Scotland and Italy.
"These are extraordinary times," SA Rugby president Mark Alexander said.
"If this had been an ordinary year, we would not have had this meeting.
"But we needed to take radical steps to avoid financial meltdown because of the COVID-19 crisis."
The three-time Rugby World Cup-winning Springboks will remain part of the Southern Hemisphere Rugby Championship for the foreseeable future.
New Zealand Rugby chief executive Mark Robinson said that South Africa's position was no surprise.
"SARU has signalled for some time now they were looking at aligning with the northern hemisphere season," Robinson said in a statement.
"All of the SANZAAR partners had agreed to look at more domestically related competitions in 2020 and 2021.
"During times like these change is inevitable and we need to be willing to adapt quickly.
"We were thrilled with how Super Rugby Aotearoa was received this year, and are excited about what is shaping up for 2021.
"We're also pleased to hear confirmation of South Africa's ongoing commitment to remain a key partner in SANZAAR... we look forward to seeing the Springboks in action during the upcoming Rugby Championship in Australia."