I am an EU citizen planning to fly from Switzerland to England (London). I usually use the app from my airline to do online check-in and then just walk up to security. In this case, though, the airline is requiring my passport information to complete the online check-in. This never happened to me before.

Looking online, it seems that I need to provide my passport information as part of the API (Advanced Passenger Information) required to travel to the UK and other countries. I can do so, but I would rather bring my national ID than my passport on my travel (I am allowed to do so, being an EU citizen). I am wondering if this is allowed.

So my questions are:

  1. The API regulation was introduced in 2006. Why is this the first time that my airline has required me for the passport information before doing the online check-in?
  2. If I input my passport information for the API, can I travel there with my national ID and leave my passport at home?
  • 6
    For the record, Great Britain is not a country. It is a landmass. The United Kingdom [of Great Britain and Northern Ireland] is a country, however. Commented Feb 14, 2018 at 15:40
  • @LightnessRacesinOrbit Thanks. I always get confused!
    – Ant
    Commented Feb 14, 2018 at 17:00
  • 4
    Even the British... er, I mean, the UK government gets confused, and GB is very regularly conflated with the UK - for example, Team GB at the Olympics includes Northern Irish athletes; the international vehicle registration code for the UK is actually GB; even NATO and the ISO use GB or Britain to refer to the UK.
    – HorusKol
    Commented Feb 14, 2018 at 22:03
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    @smci - the geographical Great Britain includes neither the Republic of Ireland nor Northern Ireland.
    – HorusKol
    Commented Feb 15, 2018 at 6:35
  • 3
    @smci You may be confusing the geographical term Great Britain with the geographical term British Isles.
    – Jan
    Commented Feb 15, 2018 at 8:17

2 Answers 2


Wherever it asks for your "passport number", just put in your ID card number instead.

"Passport number" is a generic term, which really means "travel document number". So don't take it too literally.

So no need to complicate this: again, just put your ID card number in the API system.

  • 1
    Additionally, often there is also a field "document type". I usually travel from CH to UK with just the ID (and I put ID on API), and never had problems, so I confirm the answer. Just that in many airports the ID is now annoying: it requires you to make long queue, instead of going into automatic biometric stands. Commented Feb 14, 2018 at 10:30
  • @GiacomoCatenazzi The only problematic airline is Pegasus, which asks for the document type and then refuses to accept non-Turkish ID cards. Not API though (I was flying Zurich-Istanbul-Ercan), so could have "pretended" my ID was a passport, but went to the check-in desk instead, where they processed it manually.
    – Crazydre
    Commented Feb 14, 2018 at 10:48
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    @GiacomoCatenazzi Also, at Stansted I just use the non-EU queue, which is often empty. Sometimes get scolded for it, but always send a complaint to the Border Force with the officer's 4-digit number everytime it happens. I always get an apology.
    – Crazydre
    Commented Feb 14, 2018 at 12:09
  • +1 Alright, I see. Thanks :-) I'm still curious to know what happens if there is a mismatch (i.e. submitted API with passport, show up with national ID), but anyhow this solves my problem.
    – Ant
    Commented Feb 14, 2018 at 13:16
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    @Ant In my experience they don't check the document numbers at the gate, but if you have checked luggage you'll Need to clear bag drop and I don't know about that one
    – Crazydre
    Commented Feb 14, 2018 at 13:20

As outlined in a related question, airlines never bother checking the details you've entered during online check-in. They're essentially junk as they'll be written over anyway when they scan your passport or ID card at the gate. So feel free to enter whatever you want into the field, just make sure to keep your citizenship correct so that you're not asked to check-in at the gate (usually an issue with low cost airlines).

And yes, you may certainly travel with an ID card anywhere within the EU. Lots of travelers from countries which issue ID cards don't even have a passport so restricting passengers to using passports would be quite harmful to the airlines revenue.


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