HMS Sirius was the flagship of the First Fleet, which set out from Portsmouth, England, in 1787 to establish the first European colony in New South Wales, Australia.

[3] Berwick had a burthen of 511 83⁄94 tons (bm) and, after being burnt in a fire, was bought and rebuilt by the Royal Navy in November 1781, retaining her original name.

[4][5][6] Sirius sailed from The Motherbank, Ryde, Isle of Wight on 13 May 1787 as the flagship of the eleven-vessel First Fleet, under the command of Captain Arthur Phillip (Governor-designate of the new colony).

Phillip transferred to the Armed Tender HMS Supply at Cape Town,[7] with Second Captain John Hunter[8] remaining in command of Sirius.

Also on board were Marine Major Robert Ross, who would be responsible for colony security and surgeons George Bouchier Worgan and Thomas Jamison.

Midshipman Daniel Southwell recorded that Sirius was carrying the Larcum Kendall K1 marine chronometer used by Captain James Cook on his second and third voyages around the world.

[9] She arrived in Botany Bay on 20 January 1788, two days after Supply, according to the journals of Hunter[10] and First Lieutenant (later Rear Admiral) William Bradley[11][12] The 252-day voyage had gone via Rio de Janeiro and the Cape of Good Hope and covered more than 15,000 miles (24,000 km).

The colony was established at Sydney Cove in Port Jackson when Governor Phillip arrived on 26 January aboard Supply.

After obtaining wood and fresh water, the French left on 10 March for New Caledonia, Santa Cruz, the Solomons, the Louisiades, and the western and southern coasts of Australia.

Sirius left Port Jackson under the command of Hunter on 2 October 1788,[8] when she was sent back to the Cape of Good Hope to get flour and other supplies.

[17] Bas-relief memorials to the ship were erected in the Sydney suburb of Mosman, Norfolk Island and Ryde, Isle of Wight in 1989, 1990 and 1991 respectively.