I never thought of that before...but I would guess it's just for dinner. I'm not a big jean person...and couldn't imagine wearing jeans or pants durring the day on the ship anyway...but then again we cruised durring Sept...and I'm sure the temps are a little diffrent now that it's Feb. But anyway back to your question...I'm guessing it is just dinner. When we went into the dinning rooms for lunch and breakfast...we wore shorts, and didn't give it a second thought.