For any Dopers who’ve done a Caribbean cruise before (which I may this November):
Suppose you depart from, say, Florida, and hit up Bahamas and a bunch of other small foreign nations on your cruise, before returning to Florida. Did you have to go through Immigration/CBP re-entry (passport, everything) upon return just like as if you had flown directly on a plane from a foreign nation to America?
Of course.
In fact, when we go to St Martin (by air) we go through customs/immigration leaving and returning. Additionally, when we take a ferry from St Martin to the neighboring island of Anguilla, a 15 minute ferry ride, we go through customs/immigration on arrival in Anguilla and then again on return to St Martin.
I’ve kayaked about halfway to Anguilla from St Martin and wonder what kind of trouble I’d get into if continued and I landed on a beach in Anguilla, avoiding customs/immigration.
ETA: on a cruise, since you are arriving and departing multiple ports, there is a guy on your ship who handles “document checks” for everyone on the ship. Before the ship enters a port, a tender comes out to inspect and approve paperwork.
I think there is a special loophole Cruise lines have negotiated with immigration that a closed loop cruise is “sort of” not considered leaving, and does not require a passport:
https://help.cbp.gov/s/article/Article-74?language=en_US
We wanted to join my in-laws on a cruise and then take some time in the Carribean, not on a cruise (cos my wife and I not a huge fan of cruises we’d actually like to see the countries we visit). This is a huge hassle to arrange as it breaks the “closed loop”. It was a moot point in the end as the combination of hurricanes and getting pregnant meant the cruise never happened 
Nevermind…
This has been my experience. You still have to go through customs (for declaring any souvenirs you picked up along the way), but ID and birth certificate are all that are required.
I’ve gone through this several times as a Canadian citizen. I did need to have my passport, but as noted above, this isn’t currently required for US citizens.
But it’s usually also been one of the quickest trips through customs. The only reason I’ve ever had to wait is just because of the volume of people they’re processing. Even as a non-American, I’ve never gotten more than a brief glance, unlike going through customs when I fly, where they sometimes make a point of asking a lot about your plans.
Well the cruise didn’t happen due to the hurricane, but we wouldn’t have been on it even if it had as my wife was expecting (and this was the midst of Zika so we were not keen to visit the tropics)
If you go on a cruise that will include non US port you will be required to have your passport before you even get on the ship, That has been the case on the several cruises we have been on. And on reaching the last port we went through both immigration where we had to show our passport and declare any purchases made outside the US.
That depends on the itinerary and your citizenship status. For US citizens on a cruise that begins and ends in the same US port, ID and proof of citizenship ( birth certificate, certificate of naturalization , passport card or enhanced drivers license) is good enough - for the US government. That doesn’t mean that the cruise line or one of the ports can’t require a passport.
As far as Customs goes - yes, you will go through Customs. But in some ports facial recognition is used where you just walk past a screen if you are traveling with a passport- you will have to wait in line if you have proof of citizenship and an ID. I don’t remember what people who exceeded the duty-free allowance had to do.
Even though it’s not technically required that US citizens have a valid passport it’s a really bad idea to go on a cruise without one. If anything happens and you need to fly back to the US you’ll run into major problems.
When you leave the U.S. and go on a Caribbean cruise, you give your passport to the cruise line (the purser on the ship) who keeps it until it’s time for the ship to return to the U.S. In between, you use an ID card issued by the cruise line to leave and reenter the ship. You don’t actually have to show your passport or go through customs (at the island) when you visit a foreign island.
When was the last time you took such a cruise? The last one I took was in January and I didn’t give my passport to anyone - I kept it the entire time.
To the Caribbean, it was around 2017-2018?
I took Caribbean cruises in 2018 and 2019 as well - not only did I not turn my passport over, US citizens don’t even need a passport for closed-loop Caribbean cruises. You are correct that you don’t need it to get on and off the ship in ports , but you don’t give it to the cruise line either.
Maybe I’m confusing it with a transatlantic cruise. Or maybe different cruise lines do it differently. I defer to someone with a better memory than mine!!
It varies depending on the cruise line. Some hold onto them. Most don’t.
Since this is FQ, can you provide a cite of any that do?
Only anecdotal stories of people that have had it happen to them. Like this. . I know of no definitive list. I’ve only cruised with Carnival and Holland America and neither of them did.
Not a cruise, but twice while traveling I have given my passport to someone else who handled customs/immigration officials:
So both times for our convenience. Maybe some cruise lines or some ports have a similar convenience arrangement with the local authorities?
According to this, it depends on the itinerary as much as the cruise line.