The cost of your Carnival cruise does not include individual excursions. In some cases, an excursion costs the same for adults and children, while other excursions offer a reduced price for children. Carnival applies children's prices to customers between the ages of 4 and 12, and doesn't charge an excursion fee to children 3 years old and younger. All excursions must be paid for online before the cruise or after you've boarded the ship.