Customers at busy bars, clubs and restaurants in Glasgow city centre have been targeted.
More than 280 mobile phones, including iPhones, Blackberries and other smartphones have been taken between October 1 and December 11. Police revealed 58% of these incidents took place in licensed premises.
There have also been thefts of handbags, purses and wallets.
More than 200 people have fallen victim to thieves in the past few weeks and police are warning the public to keep their mobile phones safe - and out of sight.
Police say the sale of stolen goods, including mobile phones and laptops, is part of a network of serious and organised crime.
Chief Inspector Alan Porte - the officer in charge of policing the city centre - said: "We are working hard to identify those persons responsible for these thefts.
"But following simple safety precautions, such as keeping a phone in a closed handbag or zipped pocket, can prevent theft."
Opportunist thieves are targeting festive party-goers in the city centre, as well as people waiting in shop, bus and taxi queues.
It is believed thieves operate in groups or pairs and use diversionary tactics, such as trying to engage people in conversation.
People are urged to keep a note of the International Mobile Equipment Identity, or IMEI, which makes it easier for police to identify a phone. The IMEI number, which is a 15 or 17 digit code, is generally found under a phone's battery.