For the vast majority of domestic travel in Switzerland in 2026, reservations are not required. You can simply buy a ticket or use a Swiss Travel Pass, hop on any train, and sit in any unreserved seat. The Swiss rail system is designed for high-frequency "turn-up-and-go" travel. However, there are two major exceptions: Panoramic Express Trains (like the Glacier Express, Bernina Express, and Gotthard Panorama Express) and International Trains (like the EuroCity to Italy or TGV Lyria to France). These routes require a seat reservation fee in addition to your ticket, often ranging from 10 to 45 CHF depending on the season. While you can optionally reserve a seat on standard InterCity trains for about 5 CHF, locals rarely do this unless traveling during peak Friday evening or Sunday afternoon windows. If you see a digital display above a seat with a station name, that seat is reserved; otherwise, it is free for the taking.