Yes, you can bring luggage on the Shinkansen, but in 2026, strict oversized baggage rules apply on the Tokaido, Sanyo, Kyushu, and Nishi Kyushu lines. If the total dimensions of your bag (length + width + height) are between 160 cm and 250 cm, you must make an advance reservation for a "Seat with an Oversized Baggage Area." This reservation is free if booked with your ticket, but if you board without one, you will be charged a 1,000 yen penalty fee and your bag will be moved to a designated spot by the crew. Bags under 160 cm (standard carry-on or medium suitcases) do not require a reservation and can be stored in the overhead racks. Most travelers find it easiest to book these seats via the Smart EX app or at a green ticket machine. If your bag is larger than 250 cm, it is not permitted on the train at all and should be sent via Japan’s efficient takuhaibin (luggage delivery) services, such as Yamato Transport.