ATMs are typically available on board cruise ships belonging to major cruise lines like Carnival, Royal Caribbean, Norwegian, Celebrity, Holland America, Princess (& many others). However, most charge considerably higher fees for use in addition to any charges assessed by your bank.
Guests can obtain Euros at the Automatic Teller Machine (ATM) on board or in port in order to withdraw the amount of money they will need, usually at a better rate than any of the Currency Exchange locations in port.
So to cut a short story even shorter, whether visiting for a day off a cruise or taking a short break on one island, the best currency for the Caribbean is the US dollar. You shouldn't need any of the local currency.
In addition to security, it's also helpful to have cash as some places — such as smaller souvenir shops or taxi cabs — don't accept credit cards. Credit card usage simply isn't as widespread as it is in the United States.
There is no need for cash. The same goes for most gratuities. Cruise lines now offer prepaid options for gratuities to your room steward and dining room waiters. So you can pay them before you even get on the ship.
So how much money do you need? The answer to this question varies a lot by person, their travel habits, spending preferences, length of the cruise and destination. Many people suggest $100 per day, and this has generally worked well for me in my cruising experiences, but there are a lot of variables to consider.
There is a $500 daily limit on cash accounts for 7+ night sailings and $300 for 2/3/4/5 night sailings. Once the daily cash limit is reached, we will call the guest and inform the guest that the limit has been reached.
A: During the time you are on the ship, you will not need to use cash or a credit card for each purchase—all incidentals, purchases and services will be charged to your stateroom folio. In port, you may wish to carry cash or a credit card to buy snacks and souvenirs.
Most slot machines will just take your cruise card, but some will also take cash. Very few cruise ship casinos are cash-only but a few do exist. (Windstar and Silversea are examples.)
Although Royal Caribbean does not give free wifi to every passenger, there are a few ways to get free wifi onboard. It's no secret that wifi on a cruise is expensive. You should expect to pay around $20 per day for Royal Caribbean's wifi package, and that's only for use on one device at a time.