I do believe that you have to be fully paid before purchasing your excursions.
and this from US Passport Agency........
Travel Documents
Don't leave home without proper identification! US Passport Agency Offices
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Proof of Citizenship/Proof of Identity
Don't leave home without proper identification. The cruise lines have a ZERO TOLERANCE POLICY regarding missing or unacceptable citizenship documents. Make sure you have all of the necessary documentation to travel. IF YOU DO NOT, YOU WILL BE DENIED BOARDING, NO EXCEPTIONS. There is no room for
flexibility on this policy. Guests who fail to provide the cruise line with proper proof of citizenship and photo ID will be denied boarding and will not receive a refund.
IMPORTANT DISCLAIMER
The information below is for reference purposes only and is subject to change at anytime without notice. You are advised to contact the cruise line for the latest requirements and if necessary the appropriate consulate, U.S. Embassy or U.S. Immigration office to inquire further about travel documents. Do not rely on the information provided below, as it could change. Check with your cruise line about the specific requirements for your cruise before you show up at the pier. Failure to have the proper documentation could result in denied boarding. If you are denied boarding you will not get a refund. Cruise Direct Online assumes no responsibility for advising guests of immigration, proof of Citizenship and Proof of Identity requirements.
Don't Have a Passport? Time to Get One!
Passport Needed For U.S. Borders
United States and Canadian citizens including newborn infants, are required to have a valid passport if traveling to any foreign port during your cruise and to re-enter the United States . An original or a certified copy of your birth certificate in lieu of a passport is acceptable for cruises to the Bahamas, Caribbean, Mexico, Canada, Alaska, Bermuda or Hawaii for now, however, a passport is required after December 30, 2006 FOR ALL CRUISES RETURNING TO U.S. AFTER DECEMBER 30, 2006, as birth certificates will no longer be an acceptable form for any destination. A passport is required now, if calling on or coming from a foreign port during your Hawaiian cruise. Passport expiration date must not occur within six (6) months of the termination date of your cruise.
IMPORTANT
• Guests sailing in mid December 2006 whose itinerary transits or ends its voyage in the United States on or after December 30, 2006 will be required to present a valid passport during ship check-in formalities.
• Guests sailing on or after December 30, 2006 will be required to present a valid passport during ship check-in formalities.
Aliens (non-citizens) are required to carry a valid passport and a valid U.S. Multiple Re-entry Visa. Guests
will need to contact the consulates of the islands/countries they will be visiting, to inquire about necessary
travel documentation. Immigrations determines the proper documents which guests must have available
in order to sail.
For information on obtaining a passport, click here:
http://travel.state.gov/passport/passport_1738.html
Hope this helps!!!!