Dual Citizen Transiting Through the Schengen to the US—Which Passport Should I Use?

Question

I know there are hundreds of posts on the internet about traveling with multiple passports, but I'm new to this and I'm hoping other dual citizens with direct experience in this stuff can give me some advice on a weird flight itinerary I have coming up.

Basically, I am a US and Polish dual citizen flying on the following route:

LYR-OSL-KEF-EWR

(I believe this itinerary is all one one ticket, though the LYR-OSL route is with SAS and OSL-EWR is with Icelandair, if that matters.)

I know the basic rules of traveling with multiple passports are:

• Show the airline check-in the passport of the place you're going
• Show border control the passport of the place you're in
• Enter and exit a country on the same passport
• Enter and exit your home country on that country's passport

If I were flying KEF-EWR (or any other Schengen/EU-US itinerary), this would be straightforward. But my itinerary (LYR-OSL-KEF-EWR) actually has me doing the following:

1. Entering the Schengen in OSL (LYR is in Svalbard, which is non-Schengen and non-EU, despite being a territory of the Kingdom of Norway) and spending the night there before my onward journey to KEF the next day
2. Transiting the Schengen from OSL to KEF
3. Exiting the Schengen in KEF
4. Arriving in the US at EWR

So my question: Which passport do I show the airline at check-in in LYR?

I can think of 3 options:

1. Show Polish Passport & Switch to US Passport In Transit – Would I want to show my Polish passport since my next transit destinations are in the Schengen (i.e., OSL and KEF) and I will be required to cross the border during my transit? But if I check in with my Polish passport for the LYR-OSL-KEF legs, will I have a chance to change my passport with the gate agent/check-in agent for the KEF-EWR leg of my flight? I obviously don't have an ESTA or US visa in my Polish passport, so I don't think they'd let me board my KEF-EWR flight unless I show a US passport anyway?
2. Show US Passport & Transit with Polish Passport – Do I just show my US passport since that's my final destination and I obviously need to use my US passport to get back into the US? But if I show the US passport at LYR and that's the data on the passenger manifest, will that cause issues for me as I enter the Schengen in OSL and exit in KEF with a Polish passport? Will the border authorities be confused as to why some John Doe from the US never crossed the border in OSL/KEF despite arriving on a flight but why some random John Doe from Poland did even though they weren't on any flight manifest?
3. Show US Passport & Transit with US Passport – Or... better yet... can I just do the whole thing on my US passport and enter Norway/exit Iceland as an American even though I am a citizen of an EU country? Is that allowed? Or am I legally required to enter the Schengen and/or EU on my EU passport?

I'm probably overthinking all of this, but it's my first time traveling after getting my Polish passport and I don't want to do anything wrong or get in trouble.

If you've made it this far, thanks for sticking it out and thanks in advance for all your advice! :)

Answer 1

When talking to someone, you can show both and stop worrying. You may be asked to enter your details in advance and will indeed need to mention your US passport to the airline because you don't have an ESTA or visa but other than that you cannot do anything wrong.

On the Schengen / Norwegian side, it really doesn't matter. I would use the Polish passport at the border itself but there is no requirement to do that and no way you can get in trouble. Nothing will be matched automatically and even if and when it is (the future Entry/Exit System or if a guard asks about entry stamps in your US passport), you can always show the Polish passport and end the discussion. There is also absolutely no problem with showing the airline the US passport and switching to the Polish passport at the border (if only to go through the “EU passports” lane).

Answer 2

Since Icelandair is a low-cost carrier, you will likely check-in online for your flights. Check in with the US passport and show that to any gate agent. You can (see below) present the US passport, but present the Polish passport at the Schengen border controls would make for an assuredly smooth experience.

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Or am I legally required to enter the Schengen and/or EU on my EU passport?

No. Until the ETIAS travel authorisation is implemented sometimes next year, you can enter/exit with any passport you hold. Poland and the US allow dual-citizenship, you are fine

If you show a US Passport at the exit controls where the stamps would indicate an overstay (you were in Schengen for more than 90 days in a 180 days period without an appropriate visa/residence permit), just show your Polish passport (or even ID Card) along with it and you will be cleared.
The same applies if your US passport doesn't bear an entry/exit stamp because you last entered/exited on the Polish one.

Will the border authorities be confused as to why some John Doe from the US never crossed the border in OSL/KEF despite arriving on a flight but why some random John Doe from Poland did even though they weren't on any flight manifest?

No. until the Entry/Exit system, which is a Schengen wide entry record database is deployed (again sometimes next year, along ETIAS), your entries as a third-country citizen are materialised by your stamps, but see above for that.

The carrier may want to check at the gate your permission of stay (Ryanair is infamous for doing this), in this case, show the Polish passport.

Answer 3

Which passport do I show the airline at check-in in LYR?

Show the passport you will use at your final destination, the US passport. Once ETIAS is in place, you'll need to show both passports for a trip like this to avoid paying for ETIAS authorization to enter the Schengen area with your US passport.

The main reason I'm posting this answer, though, is to respond to some of your comments:

it's a short stay, so I guess it doesn't really matter

You'll probably get through more quickly with the EU passport, in most cases much more quickly. There's also a more serious consideration, although for most people it is of no practical consequence: your right to enter the Schengen zone is greater as an EU citizen than it is as a US citizen.

For example, if you do not show your EU passport, the border officer can question you about the purpose of your trip, might decide that you are not credible, and might refuse to let you enter altogether. So in fact, you are arguably doing a discourtesy to the officer by requiring the additional work of evaluating your application for admission as a third-country national when in actuality you are an EU citizen. (In fact, if there are automatic passport control kiosks you won't have to take any of the officer's time if you show the EU passport.)

I wasn't sure if switching passports between flights made a difference

It doesn't. You can always update your passport information. And using one passport to clear transit border controls when you've checked in for the flight with another passport has never been a problem for me. If it ever is a problem because of an inability to match the flight manifest, just show the other passport as well.

it seems easiest to just use the US passport the whole way through to save my brain the mental gymnastics.

For me the bigger problem is the fumbling. Mentally, I find it simple to remember that whenever I'm showing a passport I should choose the one that carries with it the greater rights.

Seems that the requirement for many EU citizens to use their EU passport for entry/exit is really only extended to situations where you're entering/exiting your country of citizenship (i.e., a Polish citizen entering/exiting Poland), not for other EU/Schengen countries.

Yes, because these requirements are imposed by national law rather than by union law.

My US passport has plenty of Schengen stamps from my pre-dual citizen days, so it's not like it would be suspicious for me to use it for entry anyway.

On the other hand, the many stamps might just arouse suspicion that you have been living in the Schengen area without authorization. Certainly, if you show the US passport and they start analyzing the stamps, you would at that point want to show the EU passport to save everyone some time and effort, wouldn't you? Why not just start off with the EU passport?

Answer 4

The easiest would be to use your US passport all the way through.

The only downside is that you can't use the Schengen lines (or automated control) at immigration in Oslo and Keflavik, so you may have to wait a little longer.