The brazen thefts have occurred over the past three weeks in the western Sweden town, and police have received the reports especially from young mothers and café guests.
According to the Göteborgs-Posten newspaper (GP), the gang numbers between 30 and 40 people and is believed to stem from people who previously known to be begging in the area.
The police have made an appeal to the public, warning them of the criminal activity and how it occurs.
Typically, the thieves have targeted tables in cafes and restaurants where a mobile phone is visible on the table.
One of the gang approaches, gives a note to one of the café-goers, and while they are trying to interpret the note, another person snatches the phone.
Another common scam is when a gang member approaches a woman with a pram and begs for money, while their accomplice is robbing the mother and the pram from the other side.
The thieves almost always work in pairs, and mostly consist of women, according to GP.
The thieves act quickly, and make fast getaways, making it difficult for police to identify the criminals.