The Department of Correctional Services has reported a 93% Covid-19 recovery rate, with only 299 active cases left out of 6 944 infections.
This means a total of 6 526 inmates and officials have recovered from the virus.
To date, 120 deaths have been reported, department spokesperson Singabakho Nxumalo said on Sunday.
The department had recorded 16 new infections and nine recoveries.
In total, South Africa recorded 1 579 new Covid-19 cases with 20 more deaths, Health Minister Zweli Mkhize said on Sunday.
The additional infections pushed SA's total to a cumulative 649 793 confirmed Covid-19 cases.
"This brings the total number of Covid-19 related deaths to 15 447. We extend our condolences to the loved ones of the departed and thank the health care workers that treated the deceased patients."
He added that the recovery number stood at 577 906, which translates to a recovery rate of 88.9%.