Travellers - egos vary at sea (8)
I believe the answer is:
voyagers
'travellers' is the definition.
(voyager is a kind of traveller)
'egos vary at sea' is the wordplay.
'at sea' indicates anagramming the letters.
'egos'+'vary'='egosvary'
'egosvary' is an anagram of 'VOYAGERS'.
(Other definitions for voyagers that I've seen before include "Holidaymakers" , "Travellers" , "Those on a sea journey" , "People making long sea journeys" .)