The best luggage for a cruise is a medium-to-large hardside spinner suitcase combined with a high-quality backpack or "day bag." Hardside luggage is preferred because suitcases are often stacked high in the ship's hold before being delivered to your cabin, and a hard shell protects your belongings from being crushed. Spinner wheels (360-degree) are essential for navigating the long, narrow, and often carpeted hallways of a cruise ship. You should also ensure your bag is no larger than the standard airline checked size (62 linear inches) so it can fit under the bed in your cabin once unpacked. Your day bag is equally important; you should pack it with your swimsuit, medications, travel documents, and a change of clothes, as your checked luggage may not arrive at your stateroom until several hours after you board the ship. For shore excursions, a waterproof backpack is highly recommended to protect your electronics from sea spray or rain. Finally, consider using packing cubes to keep your gear organized in the typically small closet and drawer spaces found in cruise cabins.