In 1755 Hunter was enrolled as able seaman on HMS Centaur, became a midshipman and served on and then . While aboard "Neptune" he was present at the Raid on Rochefort in 1757, and afterwards served during cruises off Brest in 1758 and the capture of Quebec in 1759. Serving aboard "Neptune" at this time as her first lieutenant was John Jervis, who became an acquaintance of Hunter.