On most major cruise lines, children are typically charged as the 3rd or 4th guest in a cabin. This means that if two adults are paying the full "double occupancy" fare, the children staying in the same room often pay a significantly reduced rate, which can be anywhere from 25% to 60% off the standard adult price. However, even if the cruise fare is discounted or part of a "Kids Sail Free" promotion, you must still pay the full amount for port taxes, fees, and gratuities for the child, regardless of their age. Some luxury or river cruise lines charge a flat per-person rate regardless of age, while others, like Disney Cruise Line, have age-tiered pricing. It is a common misconception that infants sail for free; in reality, even a six-month-old takes up a "soul on board" spot for safety regulations and will almost always incur a base fare and port taxes unless a specific promotion is active.