Yes they are. I don't believe they are acceptable anytime the dining room, dress is casual during the day. I don't think they would not let you in the dinning room with them, as we saw many people in them at dinner. Its more frounded on by the cruisers than the crew. If you are refering to Alaska, I would say yes even on tours and trains as you would need them. We were in the Caribbean and saw many people in them at night around the ship. Have a good time, you will love this ship and the crew.