Under the command of Thomas Melvill, Britannia was one of 11 ships that departed from the United Kingdom in early 1791 as part of the Third Fleet, bound for the Sydney penal settlement. Britannia departed Portsmouth, England, on 27 March 1791 and arrived in Sydney Cove on 14 October 1791. She embarked 150 prisoners, of whom 21 died during the course of the voyage.
First whaling voyage
She afterwards went whaling in the South Seas, leaving on 24 October. She returned to Port Jackson on 10 November. On her first day out she was in company with William and Mary. They killed seven whales, but were only able to retrieve two. Britannias share of the takings amounted to 12 barrels of oil. Britannia went out again, but returned in December, not having been able to catch anything. Melvill was awarded a trophy for shooting the first whale in the South Sea. Britannia left on 7 January 1792, intending to cruise for three months, and then either sail back to Port Jackson, of for England, depending on her fortunes. She arrived home on 9 August 1793 with 118 tunssperm oil plus 1900 seal skins. In 1793 Tysack Hullock became her master, and in 1795 James Wilkie replaced him.
Second convict voyage
Britannia, under command of Robert Turnbull, departed England in early 1798 and arrived in Port Jackson on 18 July 1798. She embarked 96 female convicts two of whom died during the voyage. On 7 October 1798 she left Port Jackson, ostensibly for England.
Second whaling voyage
However, she actually went whaling just off the coast of New South Wales. She spent a little over two months at sea, perhaps some 30 leagues off shore, and returned on 29 December with 60 tons of spermaceti oil. She then left for England.
Third whaling voyage
Britannia sailed from Britain on 21 November 1800 with Turnbull, master. Britannia was at New South Wales between January and March 1801. By 10 December she was at the island of Mocco. She reported to Governor King at New South Wales that she had gathered 1300 barrels of oil. She returned to England on 7 December 1802.
Fourth whaling voyage
Captain George Quested sailed Britannia from England on 7 May 1803, bound for New Zealand. She stopped in Rio de Janeiro in June for refreshment and repairs. In May 1804 she was "all well" off the coast of New Zealand. Britannia sailed again on 17 September 1804 for the Pacific Ocean, with Nathaniel Goodspeed, master. She was on the coast of Peru 10 April 1805 in ballast. She was reported to have been well in May 1805. She returned to Britain on 9 December 1805. She was at Sydney from the coast of California 22 June 1806 after having been out 22 months. She had gathered 16,000 to 20,000 seal skins plus at least 95 tons of sperm oil.
Fate
Britannia was wrecked at 0200 on the morning of25 August 1806. The wrecking occurred on either Middleton Reef or Elizabeth Reef, some 297 miles east of the Clarence River Heads in New South Wales. She struck the reef several times before waves lifted her onto the reef where her back was broken. When the crew lowered the lifeboats, one was immediately smashed but the two others, with nineteen men in all aboard, got away. Five men stayed aboard Britannia. Two were rescued the next day while the other three found another boat, put water and biscuits on board, and launched it. The three boats with their 24 men aboard headed for Newcastle. On 29 August one of the boats, with eight men on board, separated from the other two in a gale and was never seen again. The survivors reached Newcastle on 8 September and Port Jackson on 13 September 1806.
