Marion Bay is a small township in the Australian state of South Australia at the southern tip of the Yorke Peninsula.

[citation needed] In 2008, a desalination plant was commissioned to meet the water demands of the summer tourist season.

A 60 kL/d sea water reverse osmosis plant now supplies the local caravan park, residents and businesses.

The plant was commissioned in response to declining bore water quality and associated problems of corrosion.

[8] Marion Bay is located within the federal Division of Grey, the state electoral district of Narungga and the local government area known as the Yorke Peninsula Council.