Cockburn Sound is an inlet of the Indian Ocean on the coast of Western Australia. It extends from the south of the mouth of the Swan River at Fremantle for about 25 km to Cape Peron near Rockingham and is located at . The total area of the sound is about 100 km².
It is bounded on the east by the mainland suburbs of Cockburn and Kwinana, on the west by Garden Island and Carnac Island, and includes several rocky outcrops and reefs. The Gage Roads shipping channel lies to the north.
The Perth Seawater Desalination Plant can be found here.
Reports from 2010 suggest the monitoring of pollutants was not adequate, using degradation of sea-grass since 2005 as a key indicator.
Media coverage in December 2016 indicates the leaking of firefighting chemicals from the local defence base at Garden Island could be a factor, however the report was only made available in September 2016. Prior official reports indicate the water quality was improving. However, there is doubt towards the scope of the report, as it does not include factors such as thermal stress from increased water temperature and oxygen stress as a result of climate change and localised desalination.
- "City of Cockburn History". www.cockburn.wa.gov.au. Retrieved 1 February 2017.
- "Cockburn Sound water quality on the rise despite fish kill, minister says". ABC News. 7 December 2015. Retrieved 1 February 2017.
- Murphy, Colin (2010). "Environmental Management of Cockburn Sound" (PDF). Western Australian Auditor General’s Report. Western Australian Government. Retrieved 2 February 2017.
- "WA Environment Minister unable to confirm if Cockburn Sound safe". ABC News. 16 December 2016. Retrieved 1 February 2017.