Train to Frankfurt Airport ( international flight)

The Fernbahnhof and Regionalbahnhof refer to parts of the airport train station serving different types of train travel, not different types of air travel. "Tief" is a lower level of the Frankfurt (Main) HB and it's the local S-Bahn station. If you search from Frankfurt(Main)Hbf to Frankfurt(M)Flughafen, you can take any resulting departure, with the S-Bahn probably being cheaper. Viewing details for your search results will also take you to maps of the stations.

You DON'T want an ICE (High Speed train with higher fares).
You just want the normal S-Bahn (suburban railway). You can start at any S-Bahn station, not just Frankfurt (Main) HB. Choose the station most convenient to your hotel.
Buy a ticket when you get to the station (if you don't already have a pass), there is no discount for advance purchase. And get on the first train heading in the correct direction, it is a frequent service.

"Tief" just refers to the underground platforms at the HB, used by S-Bahn trains.

There is no separate international terminal at Frankfurt airport, the few flights to German destinations use the same terminals as international flights. I see you want Terminal 1C

"Fernbahnhof" (long distance station) and "Regionalbahnhof" (local station) are just two stations at the airport a few metres apart. Both are an easy walk to the terminals. The S-Bahn trains use the Regionalbahnhof.

Lola,

It probably won't make much difference which train you use to get from Frankfurt to the airport. As I recall, if arriving at the Fernbahnhof you'll have to walk up stairs, over a sky bridge and then down to access the terminals. From the Regionalbahnhof you'll have to cross the street to access the terminals.

It's been a year or two since my last flight from there but from what I remember, departures are on the top level. There's an information booth where you can determine where the your airline is located to check-in and drop luggage. Be prepared for LOTS of walking as it's a HUGE airport. That time-of-day is close to the peak time, so leave a bit of extra time as there will likely be long queues at security and you'll also have to go through the Passport desk for your exit stamp.

If it would help, they have an App that might help you find your way around - https://www.frankfurt-airport.com/en/flights---more/transfer.detail.suffix.html/article/flights-and-more/services-a-z/easy-travel/frankfurt-airport-app.html

Happy travels!

Thanks! My mistake was in assuming that Frankfurt Flughafen has separate domestic and international terminals. I should have realized that the designations "Fernbf" and "Regionalbf" apply to the two train stations, not to the air terminal they served.

After I posted my question, I found a schematic map of the airport, showing the two rail stations, one below the other, underneath Terminal 1. This does not indicate which one is closer to 1C, but it doesn't matter since we will use the S-Bahn which arrives at the Regional train station. We will plan to arrive 3 hours in advance of our flight, and be prepared to walk quite a lot. Guess that will be our exercise for the day ( actually we will likely go for an early morning run along the river if there is a pedestrian path suitable for this).

According to the Bahn website, the fare for the ICE from Frankfurt Hbf to the Fernbahnhof is 13,50€/adult. The RMV fare for the S-Bahn is 4,80€/adult, if that makes a difference.

If you want to avoid the time it takes to go down the escalators to the "Tief" (deep or underground) S-Bahn station, there is a Regional Express (RE 29514) leaving for Saarbrücken from track 19 of the ground level of the Hbf at 10:25, arriving at the Regionalbahnhof at 10:35. Same fare (ticket) as the S-Bahn.

From the Regionalbahnhof you'll have to cross the street to access the terminals

The Regionalbahnhof is underneath the building across the access road from Terminal 1. There is a walkway/mall underneath the road; it connects the Bahnhof to the terminal. You don't cross the road, you go under it and come up just inside the outside wall of the main hall of Terminal 1.

The Fernbahnhof is farther out than the Regionalbahnhof. You go through the building above the Regionalbahnhof, then through a pedestrian bridge over the Autobahn. You probably don't realize you are going over a bridge because it is totally enclosed.