[toast0]

You still need a passport for most cruises. All the big cruises are non-US flagged with non-US crews and make a stop, if briefly, in a non-US port.

When you finish your journey, you have to go through customs and show your passport. And your passport will usually be checked before you embark as well.

[tssva]

US Customs and Border only require a birth certificate and government issued id for US citizens re-entering the US on closed-loop cruises. A closed-loop cruise is defined as a cruise leaving and returning from the same port in the US. This is the vast majority of cruises from the US.

Also many western hemisphere countries including almost all of those in the Carribean have agreements in place which allow US citizens arriving and departing via a cruise ship to need only a birth certificate and government id.

Traveling with a passport is best practice, you for instance are in trouble if miss your ship for some reason, but is not required for the vast majority of cruises from the US.

[tssva]

This is incorrect. Most cruises from the US are closed loop cruises meaning they depart and arrive back at the same port. CBP only requires a birth certificate and government issued id in these circumstances. In addition almost all countries in the western hemisphere which US originating cruises regularly visit allow US citizens arriving and departing via the cruise ship to enter with only a birth certificate and goverment id. In the Carribean the only exception which comes to mind immediately is Martinique. They used to not require a passport but changed this requirement during covid and have not gone back. Although US originating cruises do visit Martinique, I did so on a cruise in February, it is not a common destination.

[giantg2]

Yes,for most cruises. There are some domestic ones.