Mauritius will suspend all flights from South Africa, Botswana, Zimbabwe, and Lesotho from Monday until 31 December.
Arvind Bundhun, director of the Mauritius Tourism Promotion Authority, announced the decision "with regret", saying it was part of a "strict, public health-first approach".
"The government of Mauritius looks forward to welcoming visitors from these countries as soon as the public health situation improves."
The decision came as many other countries imposed travel bans on South Africa, following the announcement of a new Covid-19 variant on Thursday.
In reaction to the travel ban, South African Airways (SAA) announced that it will suspend flights to Mauritius with effect from Monday.
Apart from the service to Mauritius, SAA’s local and regional schedule remained unaffected, the airline said in a statement.
The last SAA flight on the Mauritius route will leave on Sunday. "SAA has put a bigger aircraft with a larger capacity on this route."
SAA added: "Customers who do not hold a Mauritian passport, nor residency in Mauritius but want to continue to travel to Mauritius on Sunday the 28 November 2021, will be required to sign an indemnity form on departure as SAA cannot guarantee their return as per the imposed travel ban."
Mauritius reopened its borders to international travellers on 1 October, after 18 months of closure. Since then, it has seen 100 000 visitors.