Hi Mary, A passport is not required for the 2 night cruise. If you were born in the USA an original State Issued Birth certificate (not from the hospital) and a government issued picture ID like a drivers license or state ID card...
All U.S. citizens must have valid proof of citizenship. A passport or passport card is preferred by government officials, is required for overnight stays in the Bahamas and may be required on all cruise ships in the future. For more information on passport cards please click here (http://travel.state.gov/passport/ppt_card/ppt_card_3926.html). For the cruise only, not overnight stays, a government issued birth certificate with a raised seal (not from hospital) is an acceptable form of identification if accompanied by a photo ID. Resident aliens must travel with their "Green Card" Alien registration cards. Guests from other countries must possess a valid passport and should check with their travel agent or appropriate consulate to determine other necessary travel documentation. All guests over 16 years must carry a Government issued picture ID such as a state or provincial driver's license with a picture or a government photo ID card. Again, a valid passport is required if staying overnight in the Bahamas and not just visiting for the day.
Mar 7, 2013