I don't have a good summary in mind, but this idea came to mind since I haven't really seen any good crossovers between these two.

So, I basically died and I was sent into the One Piece universe, with some bonuses offered o so kindly (not) from a R.O.Bs family. So, let's start this adventure.

When Eleanor and Delta finally escape Rapture, Eleanor becomes too powerful for Earth so the sea god, Poseidon, sends her to his personal world. There she will become infamous as... a Pirate!

Monkey D. Luffy, a former soldier who fought with the best and bravest men he's ever known, has found himself a wanted man on Earth. A person named Lutece hires him to go to a land in the sky called The New World and retrieve the One Piece in exchange for removing his bounty. Full summary inside.

Luffy, a photographer, crash lands in the middle of nowhere in the Atlantic and his curiousities lead him to a city that's seperate from the surface world. He now has to figure out Raftel's history as well as save himself from self-destruction with help.