Since 1st of January 1011 the official currency in Estonia is euro

On 1 January 2011, Estonia changes over to the euro, the single European currency. During the first two weeks of 2011, kroons and euros were equally acceptable means of payment. From 15 January 2011 the only valid currency in Estonia is the euro.

Kroons are exchanged into euros in all bank offices that offer cash services at the central exchange and without a commission fee until the end of June. Thereafter, a limited number of bank offices will continue to provide this service for an entire year. Eesti Pank will exchange kroons into euros at the central rate and without a commission fee for an unspecified term.

More information - http://euro.eesti.ee/EU/Prod/Euroveeb