The Kuna (abbreviated Kn) is subdivided into 100 Lipa. There exists coins of 1, 2, 5, 10, 20, 50 lipa and 1, 2 and 5 Kn. Notes come in denominations of 5, 10, 20, 50, 100, 200, 500 and 1000 Kn, although the 5, 500 and 1000 are rarely seen.
Most major currencies are accepted within the country, especially in airports or ferry terminals. You can pay in Euros, US dollars, Pound Sterling or Slovenian tolars, but the exchange rate will be terrible and your change will be returned in Croatian Kuna.
Most travel agencies, hotels and car rentals accept Euros; and you will not be ripped off as their services are priced in Euros anyway.
The Croatian Kuna is not exchangeable outside Croatia: you will have to acquire it in the country. All major currencies are exchangeable except for the Hungarian florint, which is not accepted in Croatia.
Most ports and stations that receive international arrivals have a convenient exchange office (Mjenjacnica), usually charging a commission of about 3%. You can only exchange cash in these offices and they are not open 24/7.
Another option for changing money is at a big hotel. They'll be very happy to help you out, as their offer terrible exchange rates and therefore make quite a bit of money on every transaction.
Banks and post offices also change money at about the same rate as exchange offices. They can also exchange Travellers cheques, although commissions vary from no charge to 5 Euros per cheque, so make sure you only bring large denominations. You will need to bring your passport as identification. One downside is that the opening hours are short (usually 8am – 7pm Monday to Friday; some banks open on Saturday mornings). The major banks in Croatia are Hrvatska poštanska banka, Banco Popolare and Banka splitsko dalmatinska.
Visa, Mastercard, Maestro, and Diners are the most commonly accepted cash cards; American Express is slightly more scarce. You'll need a four-digit PIN to withdraw money in Croatia.
ATMs (bankomat) can be found nearly everywhere in Croatia except for the most remote and uninhabited islands. You will find ATMs at all major airports and train stations in Croatia and very near to the embarkation point for ferries and buses. Locate ATMs and banks on http://croatia-atm.appspot.com.
ATMs are convenient and reliable in Croatia, but can be expensive. Some banks and credit card companies apply countless fees to international withdrawals.