Lincolnshire Police are appealing for a 40-year-old man to get in touch with them.
Darren Lock was last seen at 4.40pm on Tuesday, August 8.
He may be in the Lincoln or Skegness area.
Darren is described as 5ft 6ins tall with a beard.
He could be wearing a raincoat and a cap, and carrying a rucksack and sleeping bag.
Anyone who has information should call Lincolnshire Police on 101, quoting incident number 280 of August 8.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.
The missing persons helpline is 116 000 if you do not wish to speak to police directly.