Salzburg to Zermatt by train including Glacier Express

at which sites are you looking?

The only reservations you need are the Austrian train from Salzburg to the Swiss border, and the Glacier Express for the special scenic coaches. Normal trains don't need reservations in Switzerland, so not for the train from Buchs (Swiss/Austrian border) to Chur, just tickets.

St Moritz makes no sense, as you would have to go via Chur to get there, then double back nearly to Chur. There is no way to connect to the Glacier Express after Chur, mountains in the way!

This is doable, but it will be a very long day. I would split this over 2 days, and stay overnight in Chur. Then you can have a civilised departure from Salzburg after breakfast. The later part of the train trip from Salzburg to Buchs is also scenic, after Innsbruck especially before and after the Arlberg Tunnel. Bring food and drink for the journey

"I'm worried because its too early to book this" - that wouldn't worry me. If it can't be booked, nobody else has booked either. Just wait until you can buy tickets.

Salzburg to Zermatt by the more direct route (via Zurich) is already a long trip of 9 hours. You are adding 4 hours to that, making it into a 13-hour trip ( actually 12:55 according to bahn.de), with an uncomfortably early (5 am) departure. I honestly do not think it is worth all the trouble and extra time just to ride the Glacier Express.

We have been on a platform at Betten, one of the small stations along the route where the GE does not stop, as the train went slowly by. This is a bit more than halfway along the route heading toward Zermatt. People on the train looked bored or even asleep. With a 4 am wake up to make the train, the sleepy people would probably include your family.

If you just want to ride part of the route, without being on the named Glacier Express, you could shorten the journey time to 11:18 by heading to Andermatt and picking up a regional train to Zermatt via Visp. This would avoid the long Lôtschberg Basistunnel used on the mainline between Zurich and Visp, and would include most of the scenic Disentis to Brig section that Rick recommends.

Thank you for the responses. We already have firm accommodation reservations in both Salzburg and Zermatt so we are fairly set on just making this a long train day. It appears that getting from Salzburg to Chur on an early train is my best option. We were planning to get a Eurail pass, and while I realize that won't apply to the Glacier Express, I'm trying to make sure it would apply to the Sazlburg to Chur trip. I obviously can't search all the way out to September 1 (our date of travel) yet, but when I look on the SBB and DB websites for other Saturdays in the near future, I am getting a few options for early trains getting me to Chur in time to connect with the Glacier Express that leaves around 12:30. For instance, there are 2:30AM and 3:06AM Salzburg departures on nightjet trains, a 4:27 AM Euronight train, and most useful a 5:15 AM Regionalbahn train. When I try to search for departures on RailEurope through Rick's website to see if I could get reservations with a pass, the only departure that even shows up is the 2:30 departure, and it states that the first leg requires a reservation (night train, obviously), but there is no reservation compatible with the pass for this train. Forgive my ignorance on this, but I'm just wondering if I'm looking for things in the wrong way. Obviously, if I can't use a Eurail pass for this portion of the trip, or can't make reservations with a Eurail pass for trains that require them, then I would have to skip the pass altogether and just do point to point tickets for the entirety of our trip. Any advice is greatly appreciated. Thank you!

You can book a seat reservation for the 5:15 am Salzburg to Chur leg on OeBB.

https://tickets.oebb.at/en/ticket/travel

I just checked for early September and it is possible. You only need a reservation on the EC train from Munich to St. Margrethen; the legs before and after that are on unreserved regional trains.

Thank you!