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Together in the EU: the story of EU enlargement

How enlargement positively changes the EU

EU enlargement is one of the European Union’s greatest success stories. It has promoted prosperity, and strengthened our democracy.

With seven enlargements so far, the EU has bolstered democracy, security, and citizens’ rights, while raising overall living standards. Today, the EU brings together 27 Member States and over 450 million citizens.

A larger single market means new opportunities, more jobs, and stronger economic links. Cultural exchange has flourished, and the EU’s push for environmental and climate action has grown stronger.

As the Union continues to grow, enlargement remains a strategic investment in Europe’s stability and its future.

Celebration of the 20th anniversary of the 2004 EU enlargement

1986-2026: 40 years together

Forty years ago, Spain and Portugal became members of the EU. 

On 1 January 1986, they made the European Union their home, helping the Union grow from 10 to 12 countries. Together, they contributed to a more vibrant political, economic and cultural community.

Europe has made Spain and Portugal stronger. And our Union has changed for the better, thanks to them.

Previous enlargement anniversaries

1995-2025: 30 years of Austria’s, Finland’s and Sweden’s accession

On 1 January 1995, Austria, Finland and Sweden joined the EU, deepening political and economic integration in Northern Europe. The European Union then grew from 12 to 15 countries. Today, these three countries contribute significantly to Europe’s prosperity, security and shared values.

2004-2024: 20 years since the biggest enlargement

On 1 May 2004, citizens of 10 countries - Cyprus, Czechia, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia became citizens of the EU. It was the largest enlargement in EU history, connecting from Tallinn to Lisbon, and from Valletta to Stockholm. Bulgaria, Romania and Croatia’s accession a few years later has made our Union even stronger.

All enlargement rounds

  1. 1 July 2013
    Seventh enlargement

    Croatia joins the EU.

  2. 1 January 2007
    Sixth enlargement

    Bulgaria and Romania join the EU.

  3. 1 May 2004
    Fifth enlargement

    Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia join the EU.

  4. 1 January 1995
    Fourth enlargement

    Austria, Finland and Sweden join the EU, the successor of the EEC following the Treaty of Maastricht in 1993.

  5. 1 January 1986
    Third enlargement

    Spain and Portugal join the EEC.

  6. 1 January 1981
    Second enlargement

    Greece joins the EEC.

  7. 1 January 1973
    First enlargement

    Denmark, Ireland and the United Kingdom join the EEC.

  9. 25 March 1957
    Six founding members

    Belgium, France, Germany, Italy, Luxembourg and the Netherlands sign the Treaty of Rome, establishing the European Economic Community (EEC), the precursor to today’s European Union (EU).

This page was last updated on 12 December 2025