The Prison Fleet was a fleet of the Klingon Defense Force in the late 24th century. It was made up of prison ships and the duties of the fleet was to ferry prisoners from and to prison camps, as well as operate flying prisons. Their ships were notable for having an unusually large percentage of non-Klingons in their crews, because prison duty was considered one of the least desirable duties. Only freighter and garbage scow duties were less desirable than to serve on prison ships. However, non-Klingons served in the Prison Fleet in hopes of promotion. (RIS Bouteina)