Casuarina Prison is a maximum-security facility for male prisoners, located 35 kilometres south of Perth. Originally intended primarily for sentenced prisoners, it now also holds a large number of remand prisoners. It also provides specialist statewide services in the Special Handling Unit, Special Protection Unit, Infirmary, and Crisis Care Unit.
Casuarina opened in 1991, replacing the colonial era Fremantle Prison. Its original design capacity was for 397 prisoners, but numbers soon grew beyond that. Double-bunking of cells became increasingly widespread. By 1998, the prison population had increased to around 530. A major riot occurred on Christmas Day in 1998, which led to a $1.8 million program to strengthen security and staff safety.
The prison population continued to rise, reaching 690 in 2010. In response to the rising population, the Department built two new accommodation units, providing 128 new cells (256 beds). The first of these opened in late 2012. The next major expansion of Casuarina started in 2019, with work commencing on four new units with a total of 256 cells (512 beds). The first of these is due to accommodate prisoners in May 2020.