Yes, you are absolutely permitted to take food back to your stateroom on a Carnival cruise, and many guests consider it a standard part of their vacation routine. Whether you are grabbing a plate from the Lido Marketplace (buffet), a burger from Guy’s Burger Joint, or a few slices of late-night pizza from Pizzeria del Capitano, you are free to walk through the ship and dine in the privacy of your cabin. Even in the Main Dining Room, you can ask for your dessert "to go," and the waitstaff will often provide a plate cover for you. This is a popular option for those who want a quiet breakfast on their balcony or a late-night snack while watching a movie. Once you are finished, you should place your tray and dirty dishes on the small shelf outside your stateroom door in the hallway; the housekeeping staff (the "ninjas") will typically clear them away within an hour or two. This "self-service" room service is a great way to avoid the small delivery fee often associated with formal room service orders during late-night hours.