Croatia joined the EU yesterday 1/7/13. I don't know if that's good or bad. It does not mean they will adopt the Euro either anytime soon or ever - get your Kuna in the UK or in Croatia (I got a rate of 8.7 in the UK no commission) I was there recently, the shops do not accept Euro. However bizarrely at Dubrovnik Cilipi airport the duty free shops sell everything priced in Euro and not Kuna, so perhaps take any spare Euros to purchase any duty free if flying out of DBV.