Hey,
yes, of course you can use it.
Passes are valid in 33 countries which is very clearly all exposed in the general info-and in fact in GB it is very widely valid in about all TRAINs-not the metro/underground of London nor any TRAM=running on the streets in cities. And you also do not need to make those pesky REServ all the time-though it can be done at counter for free for IC-trains.
In some other countries validity may be restricted to some operators only
Thanks MartinM and mcadv!
@mcadv - Thanks, I just came across the complete list of countries and trains. Regarding reservations, it does appear that some trains do require mandatory reservations, although I’m not sure how current this info is? https://www.eurail.com/en/get-inspired/top-destinations/great-britain-train
If you plan to take the Eurostar to UK, please note that there is a limited number of pass holder seats on the Eurostar and on popular departures and during high season those sell out weeks, and sometimes months in advance.
The best place to see the availability of passholder seats on the Eurostar is
https://www.b-europe.com/EN/Booking/Pass#TravelWish
Thanks MartinM and mcadv!
@mcadv - Thanks, I just came across the complete list of countries and trains. Regarding reservations, it does appear that some trains do require mandatory reservations, although I’m not sure how current this info is? https://www.eurail.com/en/get-inspired/top-destinations/great-britain-train
That list is not correct. Reservations in GB are required for Eurostar, and the 2 Sleeper services; Caledonian Sleeper and GWR Night Riviera.
All other trains are either non reservable or not compulsory, walk-up travel on all operators is quite normal in UK.
You can get reservations for free at any ticket office or online by setting up an account at GWR.com
Hethrow Express is not valid with passes but there are other frequent trains serving Heathrow Airport.