Hi, Yvonne!
Travel documentation requirements vary for US, Canadian and all other Disney cruise guests. In addition to a valid passport, many countries require an entry visa based on your nationality. It is each guest's responsibility to identify and obtain all the necessary visas before commencing the cruise. Because requirements may vary, you should contact your local consulate or embassy for more information on required travel documentation for the port of embarkation and all ports of call during your cruise.
If your country participates in the Visa Waiver Program, you are now required to have a valid machine-readable passport and obtain 72-hour advance travel authorization via the Electronic System for Travel Authorization (ESTA). For a list of applicable countries and registration requirements, ESTA information is accessible online at http://cbp.gov/travel. I hope that helps you with those questions you have, and you can look online at
DisneyCruise.com for more details about non-US citizens traveling on a Disney ship.
As far as Disney Dollars, they are dollar-for-dollar the same exchange rate as US Dollars, and they are accepted at Disney Cruise Line, too. Yet, they are not as much "fun" to use as they are in the parks since the ships use a completely cashless system. You would give Guest Services your Disney Dollars to pay your shipboard account.
Let me know if you think of other questions before you sail. Have a wonderful day and a magical vacation. Bon voyage!
Andi