Hello Friends, Carnival prefer that you don't wear shorts and/or gym clothes, or beach attire to the dining room. Other than that, business casual is what I've mostly witnessed on my past 8 cruises in the dining rooms. You can pretty much wear what you want if it doesn't gross out the other passengers while they are eating. Men wear suit jackets and ties to the formal night dinners. Not to worry if you don't have a jacket and tie they won't through you over the ship. It's just a nice time to dress up and SMELL GOOD!