Passport or identity card
There are no longer any frontier controls at the borders between 22 EU countries. This is thanks to the Schengen rules which are part of EU law. These rules remove all internal border controls but put in place effective controls at the external borders of the EU and introduce a common visa policy. The full Schengen members are Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden (but not Ireland and the United Kingdom) plus Iceland, Norway and Switzerland (which are not EU members) Switzerland, the latest Schengen member, opened its land borders at the end of 2008 and its air borders are expected to open on 29 March 2009.
Cyprus which joined the EU in 2004 and Bulgaria and Romania which joined in 2007 do not yet fully participate in Schengen. You will therefore need to present a valid passport or ID card to travel to those countries and to Ireland and the United Kingdom.
When entering or leaving the EU at the external borders you will need a valid passport or an ID card.
It is best to have your passport or ID card when travelling in the EU because you may be required to prove your identity. If public order or national security so require, checks at the internal borders may be carried out for limited periods.
Make sure that any children travelling with you either have their own passport or ID card or are registered on your passport.
Agreements with Iceland, Liechtenstein, Norway, and Switzerland enable their nationals to be treated in the same way as EU citizens and to travel with just an ID card or passport in the EU.
Visa
You will not need a visa for travelling within the EU.