an armchair critic, traveller, etc.

an armchair traveler

One who speaks authoritatively about traveling despite not traveling often. Don't let him discourage you when he's just an armchair traveler who's never been out of the country!
See also: armchair, traveler

an armchair critic, traveller, etc.

a person who knows about a subject only from what they have heard or read and not from personal experience: He’s what you might call an ‘armchair traveller’, having never actually been outside Europe.
See also: armchair