Most cruise lines require that children be at least 6 months old to cruise, and that age restriction can rise to 12 months on trans-Atlantic, Hawaiian, and South American itineraries. Some lines, including Viking Ocean Cruises and most river lines, do not allow children on board at all.

Even if your child is too young to take advantage of the zooming waterslides, ropes courses, or ice skating rink on board, you will still have to pay a fare. There are some exceptions. Children under 11 years of age cruise free on MSC Cruises, while Seabourn, and Cunard Line do not charge for children under the age of 2. If you do have to pay for your baby, keep in mind that the rate for a child who is a third or fourth passenger in a cabin is often reduced by as much as 50 percent.

Cribs or portable playpens are available upon request, but depending on all of the other paraphernalia you bring along for baby, they can make for a tight squeeze in some cabins. Be sure to check your stateroom's layout and square footage before booking.

One amenity that families miss on a cruise ship is a bathtub. While these are standard on Disney Cruise Line's ships, you may need upgrade to a larger cabin or suite to get one on most lines. Packing an inflatable tub that will fit in the shower is one option. Lines such as Costa Cruises, Hapag-Lloyd, and Cunard also have baby bathtubs available to borrow while on board.

Look for cruise lines that sell diapers and wipes if you prefer not to pack enough for the entire trip — just be aware of the hefty price you'll pay for the convenience. Carnival and Norwegian have these items for sale on board, and with Royal Caribbean, Holland America, and Disney you can arrange to have them delivered to you when you arrive. Disney also has Diaper Genies available to borrow at no extra charge.

Your little one has likely just started eating solid foods, but is not ready to, say, help themselves at the buffet. You can request fresh pureed baby food from Disney and Cunard for no extra charge, while those lines plus Royal Caribbean have jars for sale on board.

If you want some alone time with your partner during the day, you'll have to choose a ship with a nursery that allows drop-off. While kids clubs are pretty much standard across the mainstream lines, most won't allow you to leave children under the age of three. Don't give up on your dream of quiet drinks by the adults-only pool, though. The nurseryies on Disney and Royal Caribbean ships welcome children age 6 to 36 months. Norwegian now has nurseries on their ships with play areas for little ones, but drop-off is only available on Norwegian Escape. MSC's nurseries will take children starting at 1 year. Unlike the general kids clubs, which are complimentary, you will have to pay an hourly fee. Reservations are also required, and slots fill up quickly.

For those with candlelit dinners and drinks in the lounge on the agenda, make sure to choose a ship that offers babysitting services. This is typically done in the nursery if the ship has one, with a limit of four hours and comes with an additional fee. Some lines, such as Royal Caribbean, also offer in-cabin evening babysitting (for tots 12 months or older) for a premium.

You'll find that most lines do not allow children that are still in diapers into the main pools — even if they are wearing swim diapers. If your baby likes to make a splash, look for a ship with a designated pool that caters to babies and toddlers — some Disney Cruise Line, Carnival Cruise Line, Norwegian, and Royal Caribbean ships have them.