Tantalus V is a planet in the Tantalus system. The planet is home to an Earth Federation penal colony. The facility contains a mix of surface and underground structures; patient housing, therapy, and staff offices are located underground. Above ground structures included the elevator head through which one accesses the patient facilities, as well as other buildings. Like all penal facilities, the Tantalus colony is protected by a force field that inhibited transporter traffic. To visit the planet or transfer cargo, it was necessary to contain Tantalus personnel and request the field be deactivated. Several criminals from the Avatar's world were transported to this world, including several Fire Nation generals.