If you are looking for an unusual wedding, this idea may interest you. It is about getting married on a boat, and I don't mean just the first time, but you can do the same in vow renewal or in 25 or 50 years of marriage. And if you consider it well, in addition to the wedding you will be celebrating the honeymoon.
One thing to keep in mind is that It will be the captain who will officiate the liaison, and although it is true that this fact is among his attributions or functions, in fact this ceremony does not always have legal value. In Spain, if it is celebrated in national waters, it does, then you will have to go through the civil registry to formalize the situation.
But if it's about romance, I liked the idea proposed by MSC Cruises to prepare a surprise ceremony on board any of their ships. With the excuse of inviting one of the bride and groom to a cocktail with the captain, he will be surprised with a symbolic celebration ... yes with cake and all.
One of the advantages that I find in this type of wedding is that there are usually not many guests, but a disadvantage is that you cannot get rid of them, and that they even accompany you during the honeymoon ... but even that is solvable, because they can be with you for a few days and then disembark.
And now the details of the wedding. The companies have been organizing this type of ceremony for many years, and usually have even one person exclusively dedicated to your demands. They will offer you flowers, music, decoration of rooms, menus, just as if you organize it on land. Of course, do not forget the wedding suits, but without problems with the dry cleaning issue!
As for the destination, as I said at the beginning, think a little about the place where you would like to spend your honeymoon. From everything I have found, there are numerous cruise wedding packages for the Caribbean islands and the Mediterranean.