My girlfriend and I (we are Croatian citizens) are going to visit Bucharest, Romania and we plan to stay there for 1 week. We will be traveling from Croatia to Budapest, Hungary first and from there we will take a plane to Bucharest.
Can we do this with our ID cards from Croatia? I did some research and we should be able (from what I found). Since this will be our first flight I just wanted to be sure since she and I don't have valid passports (they expired).
If you are Croatian citizens then yes, you can do this. A valid national ID card is sufficient for any EU citizen to enter any other EU country.
This is specified in directive 2004/38/EC. Article 5(1) says:
Article 5
Right of entry
Without prejudice to the provisions on travel documents applicable to national border controls, Member States shall grant Union citizens leave to enter their territory with a valid identity card or passport and shall grant family members who are not nationals of a Member State leave to enter their territory with a valid passport.
No entry visa or equivalent formality may be imposed on Union citizens.
(emphasis added)
