SARK resident Steve Grey is missing in Dorset.
The 51-year-old travelled from Guernsey to Poole on a planned trip on 27 March.
Since then, he had been staying in hotels, but has not been seen or heard from since Saturday 8 April.
He is described as white, five feet seven inches tall, of medium build and with long grey hair and a beard. He was last seen wearing beige trousers, a grey woollen jumper and boat shoes.
Police Inspector Steve Horton, of Dorset Police, said: ‘For Steve not to have contacted anyone recently or update his social media is completely out of character and I am appealing to anyone who may know his whereabouts to please get in touch.
‘I would also appeal to Steve directly that if he sees this appeal to contact us as we want to ensure you are safe and well.’
Anyone with information is asked to contact Dorset Police at www.dorset.police.uk, via email firstname.lastname@example.org or by calling 101, quoting occurrence number 55170050925. Alternatively contact Crimestoppers anonymously on 0800 555111 or via www.crimestoppers-uk.org.