Microwaves and other appliances are typically frowned upon in cruise ship cabins, as they present a fire hazard. On most ships, you won't even find a coffeemaker or tea kettle in your room.

Standard cabins on major cruise lines like Royal Caribbean, Carnival, and Norwegian do not have microwaves. This is primarily a strict fire safety regulation; cruise ships are extremely sensitive to electrical overloads and heat-producing appliances, which are common causes of onboard fires. Even if you brought your own small microwave, it would be confiscated by security during the boarding process. If you need to heat food or milk for a baby, you can usually find a microwave in the buffet area or ask your stateroom steward for assistance. Some high-end "Owner's Suites" or multi-bedroom villas on luxury lines may feature a kitchenette with a microwave, but these are the exception rather than the rule for the average passenger cabin.