Technically, yes, you can travel without a seat reservation on LNER (London North Eastern Railway) in 2026, but it is not recommended for busy routes. LNER operates a "Seat Sure" policy where most seats are reservable. However, they almost always reserve a small section of Coach C (Standard Class) and occasionally parts of Coach M (First Class) for unreserved passengers on a first-come, first-served basis. If the train is full and you don't have a reservation, you may have to stand for the duration of your journey, which can be over four hours between London and Edinburgh. In 2026, seat reservations on LNER are free, so there is very little reason not to make one when you buy your ticket. If you have an "Anytime" or "Off-Peak" flexible ticket, you can use the LNER app to book a seat even ten minutes before the train departs, ensuring you aren't stuck standing in the vestibule.