Nassau is the capital of the Bahamas. The island is actually a chain of hundreds of islands within the Caribbean. It is south of Florida and north of Cuba, and is a common destination for Americans throughout the year.
The type of cruise determines what documents are necessary. Vacationers on a cruise with a departure and return in the same United States city are on closed-loop cruises. For example, a departure from Miami to Nassau with the expectation of returning to Miami is a closed-loop cruise.
U.S. citizens on closed-loop cruises aren't required to present a passport; however, they will need proof of citizenship. An original or certified copy of a birth certificate, a certificate of naturalization, a passport card or an enhanced driver's license (EDL) will do. In addition, they will need to present a government-issued photo ID. Children must present proof of citizenship, and if 16 and over, a photo ID.
A standard passport is required for all other cruises. Note that if your cruise does not return to the same U.S. port, then you are required to present a passport.
For a passport, you'll need primary evidence of U.S. citizenship, such as a previous passport or a certified birth certificate from the appropriate state agency, a social security number, form DS-11, all applicable fees, two passport-sized photos and a photocopy of all of the above. A passport application can be made at an approved Passport Acceptance Facility.