Frankfurt to Nuremberg - train advice please

The general advice is that when transferring from plane to train, especially from an intercontinental flight, DO NOT buy rail tickets in advance. You cannot predict when you will get out of the airport. Taxiing, disembarking, and walking through corridors 30 minutes; immigration (passports) could be 10 minutes or 90. The plane could be on time, 1 hour late or 1 hour early. If you buy a discounted advance purchase train ticket and you miss the train, hard luck, that ticket is worthless.
Buy your ticket at Frankfurt airport station when you get there. You will pay full price, and be able to get on the next train. There are always full price tickets available up to departure time, that is what business travellers do who cannot predict when their work will end.

• Not sure where "KEF" is. If you are changing at a non-Schengen Area airport, immigration and customs is at Frankfurt.
• If you are changing at a Schengen area airport, that is where you do immigration for the Schengen area. From there to Frankfurt is intra-Schengen and no passport control on landing.
• In both cases you will not collect your bags until Frankfurt, and then go through customs there. But customs takes zero time, you will not be stopped.

KEF is in Iceland, part of Schengen, so no immigration in Frankfurt. Iceland is not in the EU, so there could be customs, but it is almost always a formality.

You can either buy an advance ticket (Saver Fare) online (!40€ for 2) for shortly after arrival, and risk losing the ticket if the flight is late or provide a large time cushion (still a little risk) and probably wait a long time at the airport if your flight is on time, or you can pay full fare (117€ for 2) for a flexible ticket and leave right away, or you can go with a regional pass and leave right away.

The last option would take 3 hours 52 minutes by regional trains, the others would use an ICE and take 2 hours 25 minutes, but it takes a few minutes longer to get to the Fernbahnhof for the ICE.

On a weekend day, the regional pass would be a Schönes-Wochenende-Ticket, for 44€. On a weekday, buy two local tickets to Kahl am Main (first stop in Bavaria) for 8:35€ each and a Bayern-Ticket for two for 31€ (47,70€ total) or a Quar-durchs-Land-Ticket for the whole trip for 52€.

Note: you would probably be ahead time-wise to just take the regional option vs waiting around for a later ICE.

The cheapest way of travelling would be with an "Quer durchs Land" - ticket (€52 for two, restricted to regional trains, valid after 9am), travel time, however, is 3:52 compared to 2:25 with ICE. Don't buy a saver fare ticket for the ICE even if the price is tempting: if your plane is late and you miss the train which your ticket is booked for you have lost your money. You could look up whether your airline participates in the Rail&Fly programm of the Deutsche Bahn. A r&f ticket typically costs €29 for one (depending on airline) to any station within Germany.

Look up train connections at www.bahn.com; type in as point of departure "Frankfurt (M) Flughafen. Long distance trains depart from the "Fernbahnhof", regional ones from the "Regionalbahnhof"; both are close together.

If you don't mind a long (just under 5 hours) bus ride there are Flix buses from the Airport to Nuremberg. A ticket for two Is usually just under 60E.

Wow thanks for the quick responses! Sounds like it will be better for us to just wait until we get there.

Yes, stopping through Iceland. Thanks for letting me know that most processing will happen there.

Also, after a few days in Nuremberg, we will be making our way by train to Strasbourg, France for a couple of days. Same philosophy there on the train ticket? Play it by ear? Or because we will be coming from our hotel and will be at the mercy of our own schedules, and not at the mercy of the airlines being on time, do we buy that one in advance? Less options for trains, it seems, after a quick google search. Although if we had to postpone a day due to scheduling, it wouldn't be the worst thing in the world to have to spend an extra day in Nuremberg...haha ;-)

dont rely on a google search on that second trip. Go to the German railroad site - bahn.com, and see all the trains there, as well as available fares.

Nuremberg, we will be making our way by train to Strasbourg, France for a couple of days. Same philosophy there on the train ticket? Play it by ear?

No, the opposite. Buy in advance to get the cheap ticket. As you will already be in Nuremberg there is minimal risk you will miss the train.

DO NOT use Google for trains, it is useless. Go directly to the website of the company running the trains. In Germany this is DB (Deutsche Bahn = German Railways): https://www.bahn.com/en/view/index.shtml
You can look up times and buy tickets for train within, to or from Germany on this site.