Zuma was ordered to report back to prison and arrived at a detention facility in Estcourt, northwest of Durban, where he was "admitted into the system" on Friday, 6am local time.
But he was let go almost immediately as part of a "remission process" aiming to address overcrowding in prison, Correctional Services national commissioner Makgothi Thobakgale told a press conference in Pretoria.
"Upon admission into the system he was subjected to administrative processes .... He was then released," Thobakgale said.
Zuma was sentenced in June 2021 after refusing to testify before a panel probing financial sleaze and cronyism under his presidency but was freed on medical parole just two months into his term. He started serving the sentence early in July 2021.
deaths in riots
His jailing sparked protests that descended into riots and looting that left more than 350 dead in the worst violence to hit the country since the advent of democracy in South Africa.
The following month, he was admitted to hospital for an undisclosed condition before being granted medical parole.
In November last year an appeals court found the release was illegally granted and ordered the now 81-year-old back to the Estcourt Correctional Centre in the eastern KwaZulu-Natal province.
South Africa's prison service, which had granted Zuma's conditional release, appealed the decision, but the bid was dismissed by the Constitutional Court last month.
