eu By caspergilsing Jan 29, 1952 eu was made Jan 29, 1952 italy joined Period: Jan 29, 1952 to Jan 30, 1952 eu started Feb 18, 1952 belgium joined Mar 11, 1952 netherlands joined Mar 16, 1952 luxembourg joined May 27, 1952 germany joined Dec 12, 1952 france joined Jan 1, 1958 Treaties of Rome : EEC and EURATOM treaties Jan 30, 1967 Merger Treaty - Brussels Treaty Jan 29, 1973 UK joined Feb 15, 1973 ireland joined Nov 17, 1973 denmark joined May 27, 1981 greece joined Jan 29, 1986 portugal joined Jan 29, 1986 spain joined Jul 1, 1987 single europan act Nov 1, 1993 Treaty on European Union - Maastricht Treaty Jan 29, 1995 austria joined Jan 29, 1995 sweden Apr 21, 1995 finland joined Jan 29, 1997 treaty of amsterdam Apr 27, 2001 euro was introduced Dec 26, 2001 treaty of nice Jan 29, 2004 slovakia joined Jan 29, 2004 slovenia joined Mar 24, 2004 lithuania joined Mar 27, 2004 malta joined May 11, 2004 hungary joined May 12, 2004 cyprus joined Jul 24, 2004 poland joined Aug 27, 2004 estonia joined Sep 18, 2004 chezch republic joined Oct 19, 2004 latvia joined Jan 29, 2007 romania joined May 12, 2007 bulgaria joined Dec 13, 2007 treaty of lisbon Jun 29, 2013 croatia joined croatia finally joined the eu