My Vacation Lady will ALWAYS recommend having a passport when traveling— even if you are cruising. A passport book (not the passport card) is the best form of ID and, for adults, it’s valid for 10 years so it is certainly worth getting one if you don’t have one.
There is an exception to the rule of needing a passport when taking a cruise- if you are taking a closed loop cruise from an American port. What exactly is that? If you are cruising from Miami, or Bayonne or Galveston, for instance, and returning to the same port-that is a closed loop cruise. Technically, you can get on the ship with an original birth certificate and government issued photo ID.
Why do we recommend getting a passport? One major reason is:
If you need to be flown home due to a medical emergency or a family emergency, you will have problems returning to the US without a passport.