There is no bank on Achill Island.

There is an ATM in Sweeney's Car Park in Achill Sound near the Michael Davitt Bridge.

There are travelling banks that visit Achill, but they don't have electronic facilities so cards can't be used in them. 

The Beehive Cafe and Craft Shop in Keel offers a currency exchange service (March to October).  

Most of the shops and restaurants take credit cards. 

You might need cash for pubs and accommodation.