Last year I visited Croatia, and stayed for 7 Week's. I didn't cary cash because on previous visit's I found very convinient to use my debit card.Before my trip I deposited money in my bank account to be spent on my trip and dodn't have any problem to use ATM all along coast.One advantage was, they didn't carge me any commision for currency exchange.What card to use is usualy displayed on ATM.However I did cary some cash just in case I will be somwhere where was no ATM.Their Currency is Kuna (Kn) and current exchange rate is just about $1=5.4 Kh
Have a nice trip, and let us know how was it. I loved it.