Fellow members of her convent exclaimed "thank you Jesus" in court after Sibongiseni Phungula, 25, and Mondli Shozi, 26, were each handed life terms for the killing of Sister Gertrud Tiefenbacher.
"The accused will be removed from society for a long period of time,
deterring them from killing, raping or robbing anyone else," Judge Nompumelelo Radebe said in Pietermaritzburg High Court.
Tiefenbacher was based at the Sacred Heart Home Convent in the village of Ixopo, southwest of Durban, where she was killed last month.
The judge said the two men claimed to have been drunk during the crime and had shown no remorse.
"They have never taken the opportunity to face the nuns seated in the
gallery and ask for forgiveness. They never once turned around and took the opportunity to apologise," she said.
Tiefenbacher was strangled by the typewriter cord, suffocated with a wet towel, and left for dead in her room after being raped by the two men.
The crime shocked the small village and mission where she had lived for 50 years after leaving her native Austria.
She was buried in the village.
On Tuesday, her killers pleaded guilty to her murder and rape.
One of the accused told the court that they had gone to the convent to look for food after a night of drinking.
The pair also stole a vacuum cleaner, groceries and a watch.