What Schengen is and how it works

The boat, and the two treaties

Schengen is a village on the Luxembourgish bank of the Moselle, at the point where the Luxembourgish, French and German borders meet, and the agreement of 14 June 1985 was signed aboard a passenger boat moored there rather than in a ministry. What Belgium, France, the Federal Republic of Germany, Luxembourg and the Netherlands signed that day was short. It set an intention to end checks on people crossing the borders between them and listed measures to be taken while that was worked out, and it created nothing.

The instrument that did the work came five years later. The Convention implementing the Schengen Agreement was signed on 19 June 1990 and entered into force on 26 March 1995, and on that date the checks came off between Belgium, France, Germany, Luxembourg, the Netherlands, Portugal and Spain. Every member record here carrying 26 March 1995 carries it for that reason.

The rest arrived in batches. Italy on 26 October 1997 and Austria on 1 December 1997, Greece on 1 January 2000, Denmark, Finland and Sweden with Iceland and Norway on 25 March 2001. Nine states that had joined the European Union in 2004 had their land and sea checks lifted on 21 December 2007 and their airport checks on 30 March 2008. Switzerland followed on 12 December 2008 after a referendum on 5 June 2005, Liechtenstein on 19 December 2011, and Croatia on 1 January 2023. Bulgarian and Romanian air and sea checks came off on 31 March 2024, and the Council decided on 12 December 2024 to lift the land checks from 1 January 2025.

From a treaty between governments to Union law

For its first fourteen years the area sat outside the Community treaties: an agreement between governments, with its own convention, its own executive committee and no place in the institutions. The Treaty of Amsterdam changed that on 1 May 1999, when a protocol folded the Schengen acquis into the framework of the European Union and split its provisions between the existing legal bases. A state joining the Union after that date takes on the acquis as part of accession, which is why no member of the Union negotiates entry to the area separately.

It also explains the two exceptions on the Union side. Ireland and the United Kingdom were given protocols of their own allowing them to take part in some Schengen provisions, chiefly police and judicial cooperation and the shared database, while staying out of the provisions on border checks. Ireland kept the Common Travel Area with the United Kingdom instead, and its record shows no Schengen membership while showing accession to the Union in 1973.

What lifting the check was paid for with

An internal border that is not checked has to be compensated somewhere, and the convention did it in four ways that still stand. There is one external border with one set of rules for crossing it, now the Schengen Borders Code, Regulation (EU) 2016/399. There is a short-stay visa in a uniform format that is valid across the whole area rather than in the state that issued it. There is the Schengen Information System, a shared alert database that border officers and police query in every member. And there is the rule the visitor meets first: a stay of 90 days in any 180 is counted once across the area, so the clock does not reset at an internal crossing.

The price of admission is an inspection. Under Regulation (EU) 2022/922 a state is evaluated by teams drawn from the other members and the Commission on its external border management, its use of the database, its data protection, its visa issuing and its police cooperation, and the internal checks come off only when the Council decides unanimously that it is ready. Accession to the Union and admission to the area are therefore two separate dates on the same record, and the gap between them has run from three years to eighteen.

The apparatus is still being rebuilt. The Entry/Exit System, provided for by Regulation (EU) 2017/2226, records the travel document, a facial image and fingerprints at each crossing of the external border in place of a stamp in a passport. Its phased start began on 12 October 2025 and it was in full use across the area from 10 April 2026, which moves the counting of the 90 days from ink to a register.

Where the area stops inside a member state

Membership is a status of a state, and it does not follow the state everywhere it holds territory. Greenland and the Faroe Islands lie outside the area while Denmark is in it. Svalbard lies outside while Norway is in. The French overseas departments and collectivities are outside, as are Aruba, Curacao, Sint Maarten and the Caribbean municipalities of the Netherlands. Ceuta and Melilla are inside under special arrangements that keep checks on the crossings to the rest of Spain.

The member records show the same thing from the other side. The Dutch record carries the Aruban florin and the Caribbean guilder beside the euro, and the French one carries the CFP franc, because those currencies belong to territories the area does not reach.

The reverse case exists too. Monaco, San Marino and Vatican City are not parties to the convention and are not members here, and none of them operates a controlled border with the member that surrounds or adjoins it.

The check that comes back

The area is defined by the absence of an internal check, and the code that defines it also provides for putting one back. Articles 25 to 35 of the Schengen Borders Code let a member reintroduce control at an internal border where there is a serious threat to public policy or internal security, on notification to the Commission and to the other members. Regulation (EU) 2024/1717, in force from 10 July 2024, rewrote the limits: control for a foreseeable threat runs in periods of up to six months to a total of two years, extendable in exceptional circumstances by up to a further year, and control for an unforeseeable threat runs for up to one month and may be prolonged to three.

Notifications have been continuous at some internal borders since 2015, renewed period by period rather than lifted. The catalogue records the notifications and the limits the code sets on them, and takes no position on either.