The Schengen Agreement consists of two international treaties that have been in force since 1995:

- the Schengen Agreement of 1985 for the gradual abolition of border checks at the signatories’ common borders and

- the Convention implementing the Schengen Agreement of 1990 on a common security and asylum policy.

The Schengen Acquis (the Schengen agreements and the rules for implementing them) became part of EU law through the Treaty of Amsterdam on May 1, 1999. Since then, all new EU Member States must integrate the Schengen Acquis into their national legislation.

The Schengen Area currently consists of 27 states which have fully adopted the relevant regulations (as of March 2024): Austria, Belgium, Croatia, Denmark, Germany, Estonia, Finland, France, Greece, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Sweden, Switzerland, Slovakia, Slovenia, Spain, Czech Republic, and Hungary.
The EU Member States of Bulgaria, Romania and Cyprus have not yet fully applied the Schengen acquis. Ireland is not a party to the Schengen Agreement but has implemented some of its regulations.

Source: Auswärtiges Amt, edited (not available in German)