Cruise lines have strict minimum age policies that apply to infants as well as guests under 21 years of age. These age limitations vary by both cruise line and type of itinerary. Some cruise lines also require minors to produce specific documents at time of boarding. It's important to be aware of all of these age and documentation requirements to avoid being denied boarding without refund at time of embarkation.

Complete age and documentation requirements can generally be found on the cruise lines' websites, often under "FAQ" or in the Passage Contract. Make sure to ask your travel agent or contact the cruise line for complete and current requirements information. If you are pregnant, check with your travel agent or the cruise line for rules that may also affect your ability to sail.

Here are the age requirements for many of the major cruise lines:

Carnival Cruise Lines: Infants must be at least 6 months of age when boarding all cruises except Transatlantic, Hawaii and South America cruises, which have a 12 month minimum age. Guests under 21 years of age at time of boarding must have a parent or guardian who is 25 years of age or older in the same stateroom. The only exceptions are married minor couples and domestic partner/same-sex union minor couples. For more information, visit Carnival's website at www.carnival.com.

Costa Cruise Line: Infants must be at least 6 months of age when boarding all cruises except trans-ocean crossings, world cruises, cruises of 15 days or more, and any other itinerary Costa believes could pose a serious risk to infants. These have a 12 month minimum boarding age. All guests under 21 years of age when boarding must be accompanied by a parent or guardian in the same stateroom. On some sailings, even guests 21-24 years of age must have at least one person in the stateroom who is at least 25 years old and will agree to be responsible for the under-25 year old guests. For more detailed information, visit www.costacruise.com.

Holland America Line: Infants must be at least 6 months of age when boarding all cruises except trans-ocean crossings and any other itinerary that Holland America believes could pose a serious risk to infants. These have a 12 month minimum boarding age. All guests under 21 years of age must be accompanied by a parent, guardian or chaperone who is at least 25 years of age. One adult (age 25) chaperone is required for every five persons under the age of 21. Minors under 18 cruising to certain foreign countries must be traveling with both parents or must present a notarized letter of consent by one or both parents who are not accompanying the child. Additional documentation requirements apply. For more extensive information on all document requirements for minors and other minimum age details, visit www.hollandamerica.com.

Norwegian Cruise Line: Infants must be at least 6 months of age when boarding all cruises. All guests under 21 years of age must be accompanied by a passenger age 21 or older who "expressly agrees to be responsible for the under-21 passenger throughout the cruise." This older guest must be sharing the same or connecting stateroom with the under 21 passenger. Rules are waived for married couples under 21 years of age with proof of marriage required. Rules are slightly different for those cruising under the family plan - see website for details. Minors under 18 must be traveling with both parents or must present a notarized letter of consent by one or both parents not accompanying the child. The letter must also authorize medical treatment in case of emergency. Additional documentation requirements apply. For more extensive information, visit www.ncl.com.

Princess Cruises: Infants must be at least 6 months of age on Alaska, Canada/New England, Caribbean, Europe, Mexico, Trans-canal and Australia/New Zealand cruises and at least 12 months of age on all other cruises. All guests under 21 years of age must be accompanied by a passenger at least 21 years of age or older "who shall assume responsibility for their care during the cruise." For more detailed information, visit www.princess.com.

Royal Caribbean International and Celebrity Cruises: All infants must be at least 6 months old at time of boarding except for Transatlantic, Transpacific, Hawaii, selected South American cruises/cruisetours, and other selected cruises/cruisetours. These have a 12 month minimum boarding age. "Denial of boarding for infants who do not satisfy these minimum age requirements may also result in the denial of boarding for one or more guests sailing with that infant" without refund. All guests under 21 years of age must be accompanied by a passenger of at least 21 or older in the same stateroom. This age requirement is waived for minor children sailing with their parents or guardians in adjacent staterooms or married couples less than 21 years of age with proof of marriage required. For more information, visit www.royalcaribbean.com.