Hunter was a midshipman with Admiral Durrell on his flagships, the "HMS Royal Ann", "HMS Princess Amelia" and the "HMS Royal George". Durell made Hunter the master's mate in his new ship, the "HMS Launceston". He served in North America and by 1768 was the ship's master. He served on the "HMS Carysfort" at Jamaica from 1769 to 1771. He went to the East Indies on the "Intrepid" from 1772 to 1774. He then served in the "Kent" and the "Foudroyant". He returned to North America and was on the "HMS Eagle" with Admiral Lord Howe. With Howe's help and support, Hunter was finally made a lieutenant, 20 years after he passed his exams. Officer jobs were hard to get; there were more officers on shore on half pay than there were serving on ships.