We would recommend bringing a reasonable amount of local currency (Euros) with you as quite a few traditional Greek tavernas, cafe and small shops on the islands usually only accept euros. There are a number of cash/ATM machines on the Ionian islands including right by our base in Lefkas Town as well as in Fiscardo, Nidri, Sami, Vathy, Ithaca, Vasiliki, Paleros, Gaios and many on Corfu. There are also a number of the larger towns and islands across the Saronic and Cyclades sailing areas that have ATM/cash machines.