Welcome aboard, Rebecca! I get this question quite often and I wondered about this myself the first time we set sail with Disney Cruise Line! The answer is yes, you may pack a plastic toy pirate sword for your little guy to use on Pirate Night.
You'll see in
Disney Cruise Line's list of Prohibited Items that swords and other weapons or realistic replicas of weapons are not allowed onboard, for obvious reasons. However, a very obvious plastic kids' pirate sword is fine and you'll see many little guys running around sporting those on Pirate Night.
I always pack my son's toy sword and pirate hook in our checked luggage - just in case! But we've never had a problem bringing those. And you'll also find many different toy pirate swords and hooks as well as other swashbuckling costumes and accessories for sale in Mickey's Mates, the gift shop onboard the Disney Wonder.
Pirate Night is such an exciting night for the whole family, so bring your pirate best, or purchase new gear onboard and get ready for a great time!
Have fun as you continue to plan, Rebecca! I'm happy to help if you have any other questions before you set sail!