The passport-free zone within the European Union has made travel between European countries simpler and quicker. Internal borders have become essentially dissolved for those with a Schengen visa, while the external borders have tightened their border checks for anyone that is not a citizen of one of the member states. For some European passport holders, however, the passport-free zone has also increased confusion about whether they need to pack a passport on their trips between countries.

Schengen Area

The passport-free area of the European Union is known as the Schengen Area. If you hold a passport from one of the EU countries, you do not need to show a passport or other travel documents when traveling between countries within the Schengen zone. At the time of publication, the 26 Schengen countries were Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and Switzerland.

EU Countries Requiring Passports

Certain countries in the European Union do not belong to the Schengen Area, and EU nationals must show their valid passports – or other valid national ID – to border controls when entering or exiting these countries. At the time of publication, European nationals must show their IDs when entering or exiting the United Kingdom, Ireland, Cyprus, Croatia, Bulgaria or Romania. The U.K.'s upcoming exit from the EU may further affect this, however the regulations have not been put in place yet.

Forms of Identification

Even within the passport-free Schengen Area, it's a good idea to carry your passport or other nationally issued ID card. You don't need to show ID at the border, but you may be asked to prove your identity if stopped by the police, or if you are boarding a plane. For border crossings outside the Schengen Area – or for proving your identity within this area -- the only acceptable forms of ID are those issued by national authorities. Identification you may use within your home country – for example, a driving license, bank card or tax card – is unlikely to be accepted in another European country.

Europeans Requiring Passports

Certain Europeans need passports or other national ID to travel between any two European countries. Passports or equivalent IDs are required to check in at European airports, even for flights within Europe. If your passport is from a European country that is within neither the Schengen Area nor the European Union, you will need to carry a passport when traveling within Europe. As of January 2018, Montenegro, Serbia, Turkey, the former Yugoslav Republic of Macedonia, Bosnia and Herzegovina and Kosovo are the only non-E.U. and non-Schengen countries that this applies to.

U.S. Travelers

Tourists from the United States are able to travel easily between any of the Schengen countries for a period of up to 90 days within any 180-day period with a valid passport. U.S. citizens should not overstay their trip, as exceeding this 90 day limit within the requisite 6 months can lead to deportation and even bans from reentering in the future. One recomendation for those looking for long term travel instead of short stays is to space out your travels between Schengen and non-Schengen countries within the period of six months.