The Spencer Gulf is the westernmost and larger of two large inlets on the southern coast of Australia, in the state of South Australia, facing the Great Australian Bight. It spans from the Cape Catastrophe and Eyre Peninsula in the west to Cape Spencer and Yorke Peninsula in the east.

Gulf St Vincent, sometimes referred to as St Vincent Gulf, St Vincent's Gulf or Gulf of St Vincent, is the eastern of two large inlets of water on the southern coast of Australia, in the state of South Australia, the other being the larger Spencer Gulf, from which it is separated by Yorke Peninsula. On its eastern side the gulf is bordered by the Adelaide Plains and the Fleurieu Peninsula.