Police said that officers were called to the prison at 530pm yesterday, after reports that three people in a grey Mazda sedan were behaving suspiciously behind the facility.
One man allegedly got out of the car with a bow and arrow and attempted to shoot a package into the prison.
Police said the man attempted to run from the scene but was arrested nearby.
The car drove off but was also found nearby.
A 32-year-old Ridleyton man, a 35-year-old West Croydon man and a 31-year-old Findon woman were arrested.
All three were charged with introducing contraband into a correctional facility and will appear in the Port Augusta Magistrates Court today.
The package has been seized and will be analysed by Forensic Services SA.
Police said new legislation introduced in June sets out that anyone found in possession of contraband or a controlled drug without a lawful excuse within a 100 metre buffer zone of any prison can face up to 10 years jail if found guilty.
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