Hey there, hi there, Megan! Welcome, and thank you for sailing by with your question.
Disney Cruise Line is about as casual as they come where the main dining room is concerned. On a three-night cruise, you won't find any formal nights (and on longer cruises, even the designated formal night is optional). For your cruise, your first night will likely be
cruise casual, and then your two themed nights.
For
Halloween on the High Seas, I've seen costumes run the gamut. There are all-out, over-the-top costumes, some with a group theme. Other people opt for a Halloween sweater or t-shirt, and I've seen some really cute Halloween dresses. Don't miss the Mickey Mouse-querade Scare-a-bration - so much fun!
Pirate Night is very similar, in that you'll find guests dressed in their swashbuckling best, and others who throw on a bandana and call it a day. You won't feel overdressed or underdressed, no matter what type of attire you choose. I also want to mention that on a three-night cruise, you'll have your regular dining room fare as opposed to a full pirate-themed menu. That makes it so you won't miss any of your dining room rotation specialty menus. But do check out the deck party!
We're so glad you cruised in to see us, Megan! Wishing you an absolutely WONDERful sailing!
Anna