Aged between 75 and 80 years old, they train by sparring and using a punchbag and eventually challenge each other in the ring.
Trainer Boitumelo Mootane said his classes aim to help the women relax as many of them lead busy lives looking after their grandchildren and "make them feel young again".
The classes are cardio-heavy and designed to both keep them fit and help with self-defence.
One of the participants Mariam Barie would advise other women her age to take up boxing.
"Just because you are a granny does not mean you need to burden yourself with that word "Granny". You need to wake yourself up and show that you are a granny with life," she said.