Euro - Background Eurozone changeover key dates - 1999/2000 Published: December 5 2001 17:06GMT | Last Updated: April 24 2002 16:33GMT January 1 1999 The euro becomes the currency for 11 member states. January 1 1999 to December 31 2001 Transition period: changeover to the euro by the whole economy. June 19 2000 Council Decision (2000/427) EC) on the adoption by Greece of the single currency.