Belgium, France, West Germany, Luxembourg, and the Netherlands signed the Schengen Agreement in Schengen, Luxembourg, launching plans to gradually abolish checks at their common internal borders.
The same five states signed the Schengen Implementing Convention, providing the operational and legal mechanisms for a borderless area (including visa rules, police/judicial cooperation, and the basis for shared information systems).
Schengen became a practical reality when checks at internal borders among the initial participating states were abolished, marking the start of passport-free travel across those internal frontiers.
The Schengen Executive Committee declared the Schengen Information System (SIS) operational and accessible to entitled authorities, a key compensatory measure enabling security cooperation without internal border checks.
EU member states signed the Treaty of Amsterdam, which (via a protocol) incorporated the Schengen rules (the Schengen acquis) into the EU framework, aligning Schengen governance more closely with EU law.
The Treaty of Amsterdam entered into force, making Schengen rules part of EU law and setting a durable legal basis for EU-level policy on borders, visas, asylum, and related cooperation.
The EU adopted Regulation (EC) No 562/2006, establishing a common code on rules governing the movement of persons across borders (the first Schengen Borders Code), helping standardize internal/external border rules.
The largest single enlargement of Schengen took effect as internal checks were lifted at land and sea borders for nine EU states (Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, Slovenia).
As the final step of the 2007 enlargement, internal air-border checks between the new members and existing Schengen states were abolished.
During the 2015 refugee crisis, Germany reintroduced border controls at its internal border with Austria, illustrating how Schengen rules allow temporary checks in response to serious threats or exceptional pressures.
The EU adopted Regulation (EU) 2016/399 (codification), updating and consolidating the Schengen Borders Code, including provisions governing temporary reintroduction of internal border controls.
The European Commission recommended a temporary restriction on non-essential travel from third countries into the EU; member states agreed to implement it shortly thereafter, affecting external-border access to the Schengen area.
Croatia joined the Schengen area, lifting controls at its internal land and sea borders; internal air-border checks were scheduled to be lifted later to match airline scheduling seasons.
Internal air-border controls for flights between Croatia and other Schengen states were lifted, completing the practical removal of internal border checks for Croatia across travel modes.
The Council and European Parliament reached an agreement to update the EU’s borders code, refining rules and timelines for reintroducing internal border controls and promoting alternative measures before resorting to checks.
EU member states agreed to lift checks at internal air and sea borders with Romania and Bulgaria, implementing partial Schengen membership while land-border checks remained temporarily.
The Council decided to remove checks on persons at internal land borders with and between Romania and Bulgaria, making both states full Schengen members across air, sea, and land borders.
Schengen Area: establishment, expansion and crisis management (1985–2023)
