In the video, posted on YouTube, two women are seen dining in a restaurant in Norwood, Johannesburg, South Africa.
A woman and a young girl then walk up to the table next to them and while another woman walks around the diners' table.
All three sit down and the two adult women start chatting and then look over to the pair of women who are already eating their food.
One of the diners who has her back to the camera is sitting with her handbag between her and the chair.
One of the thieves - presumed to be the mum - then speaks to the young girl who then gets up from the table and walks around the back of the diner's chair.
The girl stops and holds on to the back of her chair before she leans over and dips into the open handbag with her right arm. She takes a few seconds to rummage around in the bag before withdrawing a white phone.
She slips back to the table under the watchful eye of the women and zips the phone into her hooded grey sweatshirt.
The trio quickly get up from the table and leave the restaurant as the diners continue their dinner unaware that they had just been the victims of theft. The women featured in the video have not yet been identified.