Do you really need a passport when taking a cruise?
Proof of Citizenship
Legally (as it applies to US Citizens only, not citizens of other countries or resident aliens in the US), if you arrive on the same ship at the same port that you left from, and you go to certain Caribbean countries, you only need a birth certificate and ID.
However, if you miss the boat in one of the ports (think being late, ill or injured) then a passport would be extremely handy (otherwise you have to deal with embassy officials, who may or may not be working that day).
In my opinion, I would not leave my home country without it.
I always take my Passport with me...even if it stays in the cabin safe and I just have a Xerox of it on me. You never know what can happen, your late back to the ship and left behind, the ship breaks down and is towed to a foreign port and you need a passport to fly home.
Always carry your passport and another piece of ID. You never know when you are going to need it.
If you leave from a US port and come back to a US port, you do not need it. However, what if there is an emergency and you have to fly home? You can not fly everywhere without a passport. The passport card is not acceptable to fly. You need the book. We got ours in 2008 for our 1st cruise.
I don't travel outside the U.S. without a passport.
It's STRONGLY recommended, but not necessarily required. Here are the details: