Buenos Aires will be the last Southern Hemisphere city the Springboks play in before their preparations for their World Cup defence in France.
They will be playing Argentina there on 5 August, three days before the 33-man squad for the World Cup will be announced.
The fixture, the 36th between the sides, will be played at the Jose Amalfiltani Stadium and form part of this year's condensed Rugby Championship.
The match will be one of two between the sides in the tournament, with Ellis Park hosting the first game between the teams on 29 July.
South Africa will only play Australia and New Zealand once in the shortened Rugby Championship, with the Wallabies being hosted at Loftus Versfeld on 8 July.
The Boks will then travel to New Zealand to face the All Blacks at the Mount Smart Stadium in Auckland on 15 July in their first Test in the land of the Long White Cloud since the 16-16 draw in Wellington on 27 July 2019.
The Argentina Test will be South Africa's first at the home of football club Velez Sarsfield since 2015, even though they played in the Argentine capital last year, where they beat Argentina 36-20 at the Libertadores de América - Ricardo Enrique Bochini Stadium.