Four people have reported having their iPhones stolen from the premises on Saturday, June 7.
South Wales Officers wish to speak with the man in the CCTV image in connection with the thefts.
Anyone with information or the individual himself is asked to contact South Wales Police on 101 or Crimestoppers anonymously on 0800 555 111 quoting occurrence number 1400198457.
Cardiff City Centre Inspector Dave Greaves said: “Having your mobilephone stolen can be expensive, an inconvenience and on occasions it may leave victims without a direct means of communication with family and friends.
“In a crowded pub, club or concert it is very easy for a thief to steal a phone, conceal it and make off within a very short space of time.
“Please keep your mobile phone with you at all times, take particular care of yours bags and stay vigilant in order to protect their property.”
