Mamertine Prison entrance fee is 10€ for 2023. You can visit Mamertine Prison by purchasing an entrance ticket, or you can consider visiting it as part of Ancient Rome or Colosseum tours.
From the 4th c. B.C. onwards the state prison of Rome stood at the foot of the Capitol hill (see Campidoglio), on the side nearest the Foro Romano (see entry). It consisted of two vaulted chambers, one on top of the other. In the lower chamber, also known as the Tullianum (after a water cistern), we are told by the Roman historians that the Numidian king Jugurtha (140 B.C.), the Gallic chieftain Vercingetorix (46 B.C.) and Catiline’s fellow conspirators were confined. According to Christian tradition the Apostles Peter and Paul were also imprisoned here, and during his confinement Peter is said to have baptised the other prisoners with water from the Tullianum spring. Accordingly the chapel which was later constructed in the prison was named San Pietro in Carcere (St Peter in Prison) . The church above it is dedicated to St Joseph the Carpenter (San Giuseppe dei Falegnami).