Pedestrians using their mobile phones in the streets around Tooley Street and Shad Thames have been advised to remain vigilant after a spate of "cycle-enabled thefts" in the area.
The warning from Riverside Safer Neighbourhood Team was included in a recent newsletter send to residents who attend Bermondsey Community Council meetings.
"Most popular amongst thieves are smartphones such as iPhone and BlackBerry," said the note.
"Thieves have been cycling past their victims and snatching out of their hands before making off at speed.
"Please remain vigilant and don't allow yourself to become an easy target."