While you can bring a suitcase for an Interrail trip, a large backpack (50L–70L) is overwhelmingly recommended for 2026 travelers. Interrailing involves a fast-paced "hop-on, hop-off" lifestyle that requires navigating cobbled European streets, narrow train aisles, and numerous flights of stairs in old metro stations where elevators are often broken or non-existent. A suitcase can be incredibly cumbersome to drag across gravel or lift into overhead luggage racks, which are often too small for hard-shell bags. If you absolutely prefer wheels, a hybrid wheeled backpack is a good middle ground. A backpack encourages you to pack lighter, which is the "golden rule" of Interrailing. If you choose a suitcase, ensure it is a small carry-on size (35L–40L) to avoid being "that person" blocking the train corridor or struggling to find a locker at the station for a day-trip.