We just took our 3 kids on a cruise last December (ages 5, 3 and 1 at the time). We paid the 3rd/4th guest rate for them which for that cruise basically was taxes and port charges. We had a passport for all three. I was just too skeptical to travel out of the country without passports for them. We really had a great time. Would definitely do it again and our kids rarely used the kids programs. We enjoyed the vacation as a family.