Most banks are open from 9am-4pm, though a few are open longer. Branches are known for long queues and it may be worth going around lunchtime to avoid this, as banks tend to experience a lull at this time of day. All of the country’s major banks offer an online banking service where you can make transfers and manage your account.
You’ll find ATMs all over the Dominican Republic - inside and outside banks, in supermarkets, shopping malls and petrol stations. There’s usually a withdrawal limit of RD$10,000 (around US$235). Card skimming, card jamming and other types of ATM fraud are not uncommon so it may be a good idea to stick to indoor ATMs with security staff or somebody you can speak to. Most ATMs accept both national and foreign cards, though beware of fees when using the latter. Expect the number of ATMs to diminish rapidly as you get into more rural parts of the country.
Visa and Mastercard are nearly always accepted where businesses take cards, though American Express is only accepted by a few major retailers. Steer away from credit cards, as fraud is common - stick with withdrawing cash from ATMs and using your debit card where possible.