Whether you need a reservation on Trenitalia in 2026 depends entirely on the type of train you are boarding. For high-speed Frecciarossa and Frecciargento trains, as well as Intercity trains, a seat reservation is mandatory and is automatically included in the price of your ticket. You cannot board these trains without a specific carriage and seat number. However, for Regionale (regional) trains, reservations are not possible; you simply buy a ticket and sit in any available seat. For 2026 travelers using a Trenitalia Pass or a Eurail Pass, you must remember to "purchase" a separate seat reservation for high-speed legs (usually around €10–€13) to avoid heavy on-the-spot fines, whereas for regional legs, you can just hop on and go.