Commodore, governor and vice admiral
In early 1764 the British Admiralty determined that it would require a permanent naval settlement off the South American coast, in order to resupply naval vessels seeking to enter the Pacific via Cape Horn. Captain Byron was selected to explore the South Atlantic for a suitable island upon which to establish such a settlement. The South American mainland was controlled by Spain, which was hostile to local expansion of British interests; to disguise Byron's mission it was announced that he had been appointed the new Navy Commander-in-Chief, East Indies. Byron set sail in June 1764, ostensibly to take up the East Indies post. For the voyage he was granted command of the 24-gun frigate HMS Dolphin and the 16-gun sloop HMS Tamar.[6]
Byron's two-vessel flotilla crossed the Atlantic over the winter of 1764 and made its way slowly down the South American coast. The Admiralty had ordered Byron to first seek Pepys Island, reputedly discovered off the Patagonian coast by the corsair Ambrose Cowley in 1683. Byron reached the co-ordinates given by Cowley in January 1765, but there was no sign of the island and the search was swiftly abandoned.[note 1] On 5 February Byron reached the Patagonian settlement of Port Desire where he resupplied his vessels from the storeship HMS Florida.[6]
Between June 1764 and May 1766, Byron completed his own circumnavigation of the globe as captain of HMS Dolphin. This was the first such circumnavigation that was accomplished in less than 2 years.[7] His actions nearly caused a war between Great Britain and Spain, as both countries had armed fleets ready to contest the sovereignty of the Falkland Islands. Later Byron encountered islands and extant residents of the Tuamotus and Tokelau Islands, and Nikunau in the southern Gilbert Islands; he also visited Tinian in the Northern Marianas Islands.[8] A notable member of Byron's crew was Master's Mate Erasmus Gower whom Byron chose to 'take a significant part' in the ceremony when he took possession of the Falkland Islands. Byron had examined Gower for his lieutenant's examination in 1762 and was so impressed that he chose him to accompany him on his own circumnavigation (1764–65) and ensured that he was appointed as lieutenant to Commander Philip Carteret immediately afterwards in the next circumnavigation (1766–69).[9]
In 1769 he was appointed governor of Newfoundland off the mainland of Canada, an office he held for the next three years.[3]
He was promoted to rear admiral on 31 March 1775. In 1779, he served as Commander-in-chief of the Leeward Islands Station[10] during the American War of Independence. After being severely injured during a storm on his way to the West Indies, Byron unsuccessfully attacked a French fleet under the Comte d'Estaing at the Battle of Grenada in July 1779.[11] He subsequently resigned his post and returned to England, where he suffered from poor health for the rest of his life.
Byron was briefly Commander-in-Chief, North American Station from 1 October 1779.[12] He was made vice admiral of the white in September 1780.[3]