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Countries that joined the EU in 1973

Three countries joined the European Communities on 1 January 1973, the first enlargement: Denmark, Ireland and the United Kingdom.

How many3 countries
As of1 October 2026
SourceEuropean Union
Memory hook

Britain brought two neighbours, Ireland and Denmark. Norway signed the treaty too, but its voters said no in September 1972.

The full list

The 1973 enlargement 3

All three joined together on 1 January 1973.

Can you name them all?

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Not on the list

Questions

How many countries joined the EEC in 1973?

Three countries joined the European Communities on 1 January 1973, the first enlargement: Denmark, Ireland and the United Kingdom.

Which countries are on the list?

Denmark, Ireland and United Kingdom.

What is an easy way to remember them?

Britain brought two neighbours, Ireland and Denmark. Norway signed the treaty too, but its voters said no in September 1972.

Why did Norway not join in 1973?

Norway signed the 1972 accession treaty, but its government lost the referendum on membership on 25 September 1972.

More lists

Schengen countriesEU countriesEurozone countriesCountries that joined the euro after 1999EU candidate countriesECB presidentsAll lists

Each name checked against at least two sources, one of them European Union, on 1 October 2026. Next review by 1 October 2028.
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