Staff at the Dorchester prison seized packages of drugs and other items after a perimeter discovery.
Correctional Service Canada (CSC) said the packages were found on Monday.
The items included crystal methamphetamine, nicotine patches and THC.
The agency listed the institutional value of the seizure at $281,700.
Police have been notified, and the institution is investigating.
CSC explained that several tools are used to prevent drugs from entering its facilities.
Those tools include ion scanners and drug‑detector dogs used to search buildings, personal property, inmates and visitors.
The agency also reported that it is increasing measures aimed at keeping contraband out to help maintain a safe and secure environment.
