Wilson Inlet is a shallow, seasonally open estuary located on the coast of the Great Southern region of Western Australia.

[1] The inlet is a wave dominated estuary with an opening mouth that has a width of 100 metres (328 ft) with a bar blocking it from late January to August.

The majority of the catchment is contained within the Albany-Fraser geological province with the original granite overlaid with sands and laterite deposited in the Quaternary period.

[3] The inlet was formed 6000–8000 years ago when rising sea levels led to an ancient river valley being flooded.

[2] In 1911 a local farmer William Leonard Smeed and six members of his family (four adults and three children), were drowned when their small yacht Little Wonder was knocked down in a squall while sailing on the inlet near Pelican Island.

[8][9] The inlet is breached at Ocean Beach near Denmark at times to reduce the chances of flooding around the local river systems.

[13] The mouth of the inlet is dominated by stands of rushes (Juncaceae) of a single species, the South African Juncus kraussi.

[19] An earlier operation had attempted to commercially produce blue mussels in the 1970s, but the small scale raft culture was destroyed by Cyclone Alby just prior to harvest.