Do I Need a Passport?
The question of whether or not you'll need a passport to cruise today got a little more complicated. Actually that's not quite correct. More like the current complication and confusion is now going to continue at least until June, 2009.
As it stands now, most Caribbean and Mexican cruises leaving from the United States don't require a passport - only a government-issued picture ID and certified birth certificate. You may cruise or drive out of the country and return via road or sea and be just fine. However, the complication comes with air travel. If you must fly out of the US, or return via air from any foreign country (and Mexico and Canada are foreign countries), you must have a passport.
Why is this complicated for cruisers? Let's say something happens and you have to disembark from your cruise in Cozumel to perhaps seek medical treatment or fly home to take care of an emergency back home. You boarded your cruise with your birth certificate and driver's license. Oops. You need a passport to fly back. Suddenly it's very complicated.
I highly recommend anyone who plans to travel outside the country get a passport. Period. They're good for 10 years, right now the hassle isn't too bad or the delays too long to get yours processed. Yes, there's a cost, but amortized over 10 years it's cheap - about $10/year. And it gives you options - you may decide to take a wonderful deal that departs from Europe or South America at the last minute - no need to worry about getting a last-minute passport.
It's also the gold standard for ID. I no longer travel, even domestically, using any other form of ID. It speeds everything up. You have the protection that little blue book affords you with regard to embassies and consulates in other countries.
No matter what the government says is the deadline to get a passport for cruise travel from the US, I say your deadline should be NOW.