On the vast majority of Swiss trains, a seat reservation is not required and is actually quite uncommon for locals. On standard InterCity (IC), InterRegio (IR), and RegioExpress (RE) trains, you can simply board with your ticket or Swiss Travel Pass and sit in any vacant seat in your designated class (1st or 2nd). However, there are a few important exceptions in 2026. Panoramic tourist trains—such as the Glacier Express, Bernina Express, and Gotthard Panorama Express—do require a mandatory seat reservation, which carries an additional fee (often between 10 and 49 CHF). Additionally, if you are traveling on international high-speed trains like the EuroCity (EC) to Italy, the TGV Lyria to France, or the ICE to Germany, a reservation is often either mandatory or highly recommended during peak periods. For standard commutes between cities like Zurich, Bern, or Geneva, you will almost always find a seat, though during rush hour (7:00-9:00 AM and 5:00-7:00 PM), the trains can be very crowded, and paying the small 5 CHF fee for a guaranteed seat might be worth the peace of mind.