Ethan Clark, 20, was reported missing this afternoon having last been seen today at 5am at his home in Portswood.
Since then he has not been in contact with his family, who are growing increasingly concerned for his welfare.
He is described as being white, 6ft 1ins tall, of a slim build, with cropped mousey brown hair, brown eyes, a thin moustache and hair under his chin.
He was last seen wearing dark track suit bottoms, a black hooded top, a dark blue fleece, green and grey walking boots with white laces and carrying a dark blue rucksack.
Have you seen anyone matching this description since this morning? Do you know where he is?
Investigations are continuing but one line of enquiry is that he may have travelled to the North Yorkshire area so please share our appeal with any friends or family living there.
Anyone with information is asked to call Police on 101, quoting incident number 612, or Crimestoppers anonymously on 0800 555 111.