An oceanview cabin, often called an outside cabin, is a room with a window that looks out to sea. The window might be a large, rectangular picture window or one or two round portholes. The window is also the biggest difference between an outside cabin and an inside room on a cruise ship.
 
While the windows let in natural light, they do not open to let in fresh air. Typically, they’re covered with blackout curtains that keep the room dark even when it’s light outside. That way you can choose whether you want a pitch-dark sleeping environment or you'd prefer to leave the curtains open a crack so the morning light can filter in.