Ahoy Jennifer!
I called my friends at Disney Cruise Line to find out your answer, and more!
Since this is an Eastern Caribbean sailing, I was pretty sure that
Pirate Night would be on night four, but I wanted to be absolutely sure for you. I did confirm that your family should plan to dress in their piratey best on the fourth night of your cruise, after you return from your day in St. Thomas. Be sure to be up on the starboard side of Deck 12 to see the best fireworks view!
I also asked about your other cruise nights, to find out when formal and semi-formal nights are for you. These nights are completely optional; our family loves to glam it up on formal night. So, your cruise will look like this:
Saturday, March 21...
cruise casual Sunday, March 22...optional formal night
Monday, March 23...cruise casual
Tuesday, March 24...pirate night
Wednesday, March 25...cruise casual
Thursday, March 26...optional semi-formal night
Friday, March 27...cruise casual
Wishing you a FANTASTic voyage! Please let me know if you have further cruise planning questions!
Happy Cruising, Tracy V.