You can have a ceremony anywhere. For anything. Anytime.
Author Peter Merry, when writing his book, “Best Wedding Reception Ever!” asked to interview me. I told him about the four weddings:
Wedding of your hearts (when they make up their minds to get married)
Social Wedding (public statement with guests)
Legal Wedding (marriage license)
Religious and/or Traditional Wedding (specific liturgy & customs)
Most people think everything magically happens all at once. Nope. Each wedding is its own separate thing.
No matter where you have your wedding ceremony, it’s not legal until you have a completed and registered marriage license.
You can have as many ceremonies as you want. Tons. Gazillions, even. But the legal wedding happens once.
Think of the marriage license as a business contract because that’s exactly what it is. The government that issues the license doesn’t consider the contract to be romantic. Any romance comes from whatever you emotionally attach to the piece of paper.
Plus, you will be subject to the laws of where you file the marriage license. In America it’s state by state. Probably different in other countries.
If you have a ceremony on a cruise ship in international waters I’ll bet the captain/officiant won’t have a legitimate marriage license for you. Perhaps a cool certificate as a memento but it ain’t for legally real. Legal weddings on cruise ships happen when they are docked in a harbor.
Do your homework.