Corrections officers spotted a large cougar in a wooded area near the prison's perimeter in the early morning hours.
Saanich police say the cougar disappeared by the time they arrived, but the sighting was confirmed on videotape from the centre's surveillance system.
Police say they want to warn local residents that the large cat has been seen in the area.
Conservation officers weren't called in because police say the cougar appeared to be exhibiting normal behaviour and was in its usual habitat.
The almost 100-year-old prison serves as a pre-trial and remand unit for inmates of all levels of risk and holds up to 350 inmates.