Is an identity card issued to a non-citizen an acceptable document to travel within the EU?

Question

Suppose an EU citizen is resident of another member state and gets issued a national identity card identical to the ones citizens get there. (If that is not concrete enough to answer the question, assume a Finnish citizen who is a temporary resident in Estonia.)

^{This is an Estonian ID card issued to a Finnish citizen. The ones for Estonian citizens look exactly the same, just with a different entry at "citizenship" and without a small remark on the back side specifying the type of residence. I know that this is the old model that isn't valid anymore but I couldn't find an example of the new card.}

If one carries no other identity document into a country which is neither the issuer nor the country of citizenship,

1. Is it possible to cross the border from outside the EU?
2. Is it allowed to cross Schengen borders?
3. Does this satisfy the requirements to carry an ID imposed by some member states, e.g. Portugal?
4. Is it possible to get on board of an airplane in countries where a valid ID is required for this, e.g. Spain?

In short, can such a card be used just as if it had been issued to a citizen?

I know that technically you can enter the EU even without any identification at all as an EU citizen but that comes with a lot of hassle. I'm interested in how well this works in practice. Is such an identity card assumed a valid document that is waved through?

PRADO lists such a card as an identity document but not a travel document. Which consequences does this have for the holder?

Answer 1

I suspect very strongly that the consequence is that it may be used as a travel document only for citizens of Estonia. Note that the PRADO entry actually describes the card's legal status with two sentences:

Travel document issued to nationals of: EST - Estonia • EESTI •

Identity card issued to citizens of Estonia and citizens of the European Union living in Estonia and holding a valid residence document

This most likely means that the card legally functions as a travel document only if issued to an Estonian citizen. A Finnish citizen living in Estonia must travel using a Finnish ID card or passport.

However, in the context of proving EU citizenship without a proper travel document, this card would have to be among the more effective documents available.

Logically, the difference is that this document proves that Estonian authorities are convinced that the bearer is Finnish. They are not competent, however, to make a definite determination on that question; only Finnish authorities can do that. That's why only Finland can issue a proper travel document to a Finnish citizen.

Answer 2

I am a German citizen living in Estonia. I use my Estonian ID as travel document within the EU. I have used it at Riga and Tallinn airport to fly to Germany and I have used it in Germany to fly back to Riga. I hav also used it on the ferries to Helsinki and Stockholm. This is because it really only serves as an "identity document" within the EU and I do not need to prove citizenship at a border crossing. I would not try to use it if I were going to Turkey or some other country that doesn't require passports from EU citizens, but requires the ID card.