Botany Bay (Aboriginal: Kamay), an open oceanic embayment, is located in Sydney, New South Wales, Australia, 13 km (8 mi) south of the Sydney central business district. Its source is the confluence of the Georges River at Taren Point and the Cooks River at Kyeemagh, which flows 10 km (6 mi) to the east before meeting its mouth at the Tasman Sea, midpoint between the suburbs of La Perouse and Kurnell. The northern headland of the entrance to the bay from the Tasman Sea is Cape Banks and, on the southern side, the outer headland is Cape Solander and the inner headland is Sutherland Point.

The total catchment area of the bay is approximately 55 km2 (21 sq mi). Despite its relative shallowness, the bay now serves as greater metropolitan Sydney's main cargo seaport, located at Port Botany, with facilities managed by Sydney Ports Corporation. Two runways of Sydney Airport extend into the bay, as do some port facilities. Botany Bay National Park is located on the northern and southern headlands of the bay. The area surrounding the bay is generally managed by Transport for NSW.

The land adjacent to Botany Bay was settled for many thousands of years by the Tharawal and Eora peoples and their associated clans. On 29 April 1770, Botany Bay was the site of James Cook's first landing of HMS Endeavour on the land mass of Australia, after his extensive navigation of New Zealand. Later the British planned Botany Bay as the site for a penal colony. Out of these plans came the first European habitation of Australia at Sydney Cove. Although the penal settlement was almost immediately shifted to Sydney Cove, for some time in Britain transportation to "Botany Bay" was a metonym for transportation to any of the Australian penal settlements.

The First Fleet was a fleet of 11 ships that brought the first European and African settlers to Australia. It was made up of two Royal Navy vessels, three store ships and six convict transports. On 13 May 1787 the fleet under the command of Captain Arthur Phillip, with over 1400 people (convicts, marines, sailors, civil officers and free settlers), left from Portsmouth, England and took a journey of over 24,000 kilometres (15,000 mi) and over 250 days to eventually arrive in Botany Bay, New South Wales, where a penal colony would become the first European settlement in Australia.