Carnival is pretty laid back. For me on formal nights, I wear kaki or navy blue dockers, long sleeve dress shirt, nice shoes and a tie. My wife wore dressy slacks(black) & a nice top with fancy sandals. We wore the same attire in the Steakhouse, as it was a more formal atmosphere. The guy who sat at the next table wore cargo shorts, flip flops, and a Hawaiian shirt though. On casual nights in the MDR, I wore either shorts or blue jeans with a polo collared pull over. Wear what you usually wear when you go out to eat at home.