Hi Patrick, P & O passengers are fairly traditional as far as dress and the occasion go. Formal nights many if not most men wear a D.J. or dress suit with a black bow tie and white dress shirt. Informal nights they wear a tie and jacket and slacks and informal nights anything except shorts or jeans and not tank tops or T shirts. Stick to variations of these items of clothes and you will not stick out but probably be admired, especially if you are travelling alone. ... Neil.