All three Tests between the Springboks and the British and Irish Lions will be held in Cape Town, South African Rugby and the touring side announced on Tuesday.
The second and third Tests were originally scheduled for FNB Stadium in Johannesburg, with only Saturday's first Test to be staged in the Western Cape.
According to a statement from the two organisations, the decision to remain in Cape Town was made following "extensive consultation with medical experts on the risks associated with the Delta variant of Covid-19".
The matches will now take place at Cape Town Stadium on three successive Saturdays behind closed doors due to the coronavirus pandemic.
"The data pointed in only one direction," said SA Rugby chief executive Jurie Roux.
"The series has already been significantly disrupted by Covid-19 and a return to Gauteng at this time would only increase the risks.
"We now have two teams in bio-secure environments without any positive cases or anyone in isolation. To now return to the Highveld would expose the series to renewed risk."
Lions managing director Ben Calveley said: "We are fully supportive of this decision, which we believe to be in the best interest of the Test series."