There was a seizure of contraband items at Collins Bay Institution valued over $11,000.
Correctional Services Canada Assistant Warden Heather Hyndman says around 11:30 on Tuesday morning, a package containing tobacco and marijuana was seized.
The incident is still under investigation, but staff are suspecting a drone drop.
The medium security unit of the prison was placed on lockdown to allow staff to conduct a general search.
Staff seized 161.6 grams of tobacco and 80.6 grams of marijuana, valued at $11,600.
