A passport, birth certificate, or enhanced driver's license is required of everyone on board now. You used to be able to just have a driver's license, but now they want proof of citizenship.

It's easy....they are nice...and just answer the questions they ask. Make sure to write the entry number they give you down on something, or put it in your phone. If you get checked and don't have that number, they will fine you.

If you do not touch land, you do not need to call in to US Customs upon your return.