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The 2004 EU enlargement

Ten countries joined the EU on 1 May 2004, the largest single enlargement: Cyprus, Czechia, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia.

The full list

Central European (Visegrad) 4

Central European post-communist states with shared EU-accession trajectories.

• 🇵🇱Poland
• 🇨🇿Czechia
• 🇸🇰Slovakia
• 🇭🇺Hungary

Baltic states 3

Former Soviet Baltic republics acceding together.

• 🇪🇪Estonia
• 🇱🇻Latvia
• 🇱🇹Lithuania

Slovenia, Cyprus and Malta 3

Slovenia, from the former Yugoslavia, and the two Mediterranean island states.

• 🇸🇮Slovenia
• 🇨🇾Cyprus
• 🇲🇹Malta

Not on the list

• Bulgaria, Romania: Joined later, 1 January 2007, not part of the 2004 wave.
• Croatia: Joined 1 July 2013, not part of the 2004 wave.

Questions

How many countries joined the EU in 2004?

Ten countries joined the EU on 1 May 2004, the largest single enlargement: Cyprus, Czechia, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia.

Which countries are on the list?

Poland, Czechia, Slovakia, Hungary, Estonia, Latvia, Lithuania, Slovenia, Cyprus and Malta.

What is an easy way to remember them?

4 + 3 + 3: the four Visegrád states, the three Baltic states, and Slovenia with the two Mediterranean islands.

Did Bulgaria and Romania join the EU in 2004?

No. They joined on 1 January 2007.

More lists

Each name checked against at least two sources, one of them Consilium, on 28 September 2026. Next review by 28 September 2028.
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