Tunnel
- "We recently began traveling through the tunnels to avoid the guards, but many of the entrances in the city are broken. By using them, we can get to our destination rapidly, without encountering resistance."
- ―Niccolò Machiavelli regarding the tunnels.[src]

Tunnels were a means of travel in Rome and Constantinople, and were the equivalent to the Fast Travel Booths. Ezio was first introduced to the tunnels by Niccolò Machiavelli, wherein he stated that the tunnels were used to arrive at destinations rapidly, while avoiding guards. There were a total of nineteen tunnel entrances throughout Rome.
Renovations
Initially, there was only one available tunnel entrance, leaving the other eighteen to be renovated by paying a sum of florins to an architect. The three tunnels that were located outside of the Rosa in Fiore, Barracks, and the La Volpe Addormentata would be automatically renovated once the respective building fronting it was; making them the only ones that were required to be restored.
Each district could be accessed via tunnel with the exception of the Vaticano District. Every standard entrance to the tunnels looked alike, and had the letters SPQR (Senatus Populusque Romanus) engraved over their gates.
In Constantinople, all tunnel entrances were automatically renovated, allowing Ezio to freely travel between them.
Rome tunnel locations

Centro District
- Tiber Island Hideout
- Piazza del Popolo
- Augustus Mausoleum
- Pantheon
- Campidoglio
- Rosa in Fiore
- Porte Tevere
Campagna District
- Barracks
- Northern Campagna
- Southern Campagna
- Castra Praetoria
- Terme di Diocleziano
- Colle Viminale
Antico District
Constantinople tunnel locations
- Fatih Camii
- Arcadius
- Galata
- Hideout
- Galata Mosque
- Bayezid Camii
- Gul Camii
- Arsenal
- Hagia Sophia
- Hippodrome
- The Grand Bazaar
- South Port
- Polo Trading Post
Trivia
- In the novelization of Brotherhood, Machiavelli said that Giovanni Auditore discovered the tunnels.
- In Brotherhood, if Ezio made use of the tunnels, there is a brief cutscene of him opening the latch on the gate and entering, though the player was not able to see or travel through the tunnels themselves. In Revelations, the cutscene was omitted, with the screen fading to black whenever the tunnels were accessed.
- Tunnel entrances glowed white, while seen with Eagle Vision.
- In Revelations, the Galata district tunnels connected with the other districts, even though there was a large body of water between them.