An open prison (open jail) is any jail in which the prisoners are trusted to serve their sentences with minimal supervision and perimeter security and are not locked up in prison cells. Prisoners may be permitted to take up employment while serving their sentence.
In the UK, open prisons are often part of a rehabilitation plan for prisoners moved from closed prisons. They may be designated "training prisons" and are only for prisoners considered a low risk to the public.
The idea of an open prison is often criticised by members of the public and politicians. However, prisoners do not have complete freedom and are only allowed to leave the premises for specific purposes, such as going to an outside job. In Ireland, there has been controversy about the level of escape from open prisons, attributed to the use of the prison by the IPS to transfer prisoners unsuitable for open conditions but to reduce overcrowding in the closed prisons.
In Germany the "Offener Vollzug" is part of the rehabilitation process for about 16% of prisoners.