St Georges Basin is an open intermediate estuary,[2] or inland sea,[1] located in the South Coast region of New South Wales, adjacent to the Jervis Bay Territory.

St Georges Basin is a coastal waterbody located immediately adjacent to the Tasman Sea of the South Pacific Ocean, north of the town of Sussex Inlet and east of the town of St Georges Basin.

[1] The basin covers a catchment area of 316 square kilometres (122 sq mi) and contains approximately 215,079 megalitres (7,595.4×10^6 cu ft) of water over an estimated surface area of 40.9 square kilometres (15.8 sq mi); and at an average depth of 5.3 metres (17 ft).

[4] Located with the basin are six artificial reefs that range up to 2 metres (6 ft 7 in) in depth.

[1] European surveyor Thomas Florance renamed the body of water as St Georges Basin on 29 November 1827, while tracing from Jervis Bay to Conjola.