Munich to Salzburg train?

From Munich to Salzburg, you can use the Bayern ticket on regional (BRB) trains after 9:00, so no need to book in advance. You will take the Sbahn from the airport to the Munich Ost train station and connect there. It costs 34€ for the first adult, and 10€ for each additional person, up to 5 people total.

Use the DB Navigator app to see train options.

We did this in 2022 and I think it took us about an hour to get from the plane to the S Bahn in the airport train station. (We only had carry on bags.) Then we took that to the main train station in Munich. That was about 45 minutes. Then we took a packed train to Salzburg. That's when Germany was offering the 9 euro all month train pass. We didn't buy train tickets until we arrived in Munich and boy was I surprised when the ticket person said it would be 18 euros for the two of us to get from the airport to Salzburg.

It costs 34€ for the first adult, and 10€ for each additional person, up to 5 people total.

It is 32 EUR for the 1st adult and 10 EUR for additional passengers if you but from a ticket machine or use the DB app. There is a 2 EUR surcharge to buy from a human at a ticket window.

Then we took that to the main train station in Munich vs the advice Munich Ost train station

To avoid confusion, two different commuter trains (S-Bahn) depart from Munich Airport. The S8 goes eastbound and the S1 goes westbound. You can use both.

Change train to Salzburg:
S8 - Munich Ost train station (Ostbahnhof)
S1 - Munich main train station (Hauptbahnhof)

I would recommend taking the S8 and changing at Ostbanhof for the train to Salzburg. It's much less walking and much easier to find your way around.

From Munich to Salzburg, you can use the Bayern ticket on regional (BRB) trains after 9:00, so no need to book in advance.

Please note that this ticket is not valid on express trains (e.g. RailJet, ICE). Look on https://int.bahn.de/en/ for connections and prices. (The correct starting point is München Flughafen Terminal.)