The Clyde River (Dhurga: Bhundoo) is an open intermediate tide-dominated drowned valley estuary[5] or perennial river[2] that flows into the Tasman Sea at Batemans Bay, located in the South Coast region of New South Wales, Australia.

The Clyde River rises below Kangaroo Hill in the Budawang Range, part of the Great Dividing Range, within Budawang National Park, south of the locality of Sassafras, and flows generally southwards parallel to the east coast, joined by nine tributaries including the Bimberamala, Yadboro, and Buckenbowra rivers, before turning east and reaching its mouth of the Tasman Sea at Batemans Bay.

[4] The lower reaches of the Clyde River form a substantial estuary up to 30 kilometres (19 mi) from its mouth[6] which is navigable by small vessels to Nelligen, with a tidal ebb of up to 1.28 metres (4 ft 2 in).

The coastal estuary covers a catchment area of 1,723 square kilometres (665 sq mi) and contains approximately 50,737 megalitres (1,791.8×10^6 cu ft) of water over an estimated surface area of 17.5 square kilometres (6.8 sq mi); and at an average depth of 3 metres (9.8 ft).

[6] Salinity in the estuary of the Clyde River decreases with distance from the sea,[11] giving rise to suitable conditions for oyster farming.