Royal Caribbean Cruise Ships use US Dollars as the currency on board even for cruises that depart and arrive in Australia.
This means that your bill will be in US Dollars. You can pay with your credit card or with US cash. If you do use your credit card make sure they bill you in USD not Australian dollars as they include a hidden fee for the currency conversion (Dynamic Currency Conversion).
Similarly, converting currency on board can be an expensive process with rates for local destination being substantially worse than on shore or buying before you travel.
We can help you manage these expenses by offering great rates for US Dollars and the local currency in the ports that you are visiting. Budgeting the amount to take can be tricky but we have solved that by re-purchasing any left over currency at the rate that you purchased it at.
Our guide below shows the ports that Royal Caribbean visits from Australia and some spending suggestions.