Welcome aboard, Cheryl! It sounds like your getting ready to plan a magical cruise with Disney to the Bahamas! I've sailed in the Bahamas with Disney Cruise Line many times and can tell you from experience that you're in for an amazing trip! Castaway Cay, Disney's private island, is one of my favorite beaches in the entire world!
American citizens traveling out of Port Canaveral or Miami to the Bahamas with Disney Cruise Line may present either a valid U.S. Passport or valid driver's license and birth certificate to board the ship. If at all possible, I highly recommend getting a passport if you do not already have one. You can read more about the
benefits to cruising with a passport on Disney Cruise Line's website. But, the main reason my family and I don't cruise without our passports is that we want to be protected in the unlikely event that we don't get back on the ship in a foreign port. If there is an emergency medical issue with one of us, or we simply miss the all aboard time and the ship sails without us, we will much more easily be able to return home with a valid passport.
Feel free to chat with Disney Cruise Line's agents (or your travel agent) when you book your cruise about this as well, Cheryl. I hope this helps as you begin planning your trip! Let me know how else I can help before you set sail with Captain Mickey!