My BFF just went on a Disney cruise, and swim diapers weren't allowed at all. I'd double check that first. But even my cloth swim diapers don't hold pee. They're not really designed to. If you can use them on the cruise, I'd just do whatever is easiest.
They're not allowed in the pools but are required for the splash park area.
I am pretty sure our swim diapers hold everything in...I've never gotten peed on when she was wearing them, but it could have just been coincidence.
Thanks for the advice ladies!