So, you want to test out your pet's sea legs. Unfortunately, most major cruise lines don't allow pets on board unless the pet also happens to be a guide or service animal. The only line that does currently allow pets is Cunard. It has two ships that are equipped to handle animals, the QE2 and the QM2. However, you'll need to check availability well in advance because it's limited, and they only allow pets on select transatlantic crossings.
It may seem odd that more major cruise lines don't allow pets on board, but the simple truth is that most ships just aren't equipped to handle it. Animals need a place to sleep and, more importantly, a place to relieve themselves. Cruise lines have very strict health codes to follow, and this makes it difficult to accommodate pets.
Cunard's QE2 and QM2, however, are equipped with air-conditioned kennels, a kennel attendant, pet exercise areas, and the cost of pet meals is factored into the price of your ticket. There are restrictions on pet size. So if you're animal is big, you may still be out of luck [source: Pets Can Stay]. Also, pets are kept in the kennel during the entire crossing and can only be visited during specified hours, so you may not get to spend as much time with your pet as you would like.
Aside from not being equipped to handle animals, there's one other major reason that most cruise lines don't allow pets. Cruise ships visit a number of different ports during the course of their journeys. They travel to foreign countries, and a number of those countries have strict quarantine and entry requirements for animals [source: Pets on the Go].
If you love being out on the open water and you can't stand to be away from your beloved pet, don't lose hope yet. There are a couple alternatives you may want to consider. A number of charter outfits out there are more than happy to have your pet aboard as long as it's well behaved. If you're considering a shorter day trip, there are many sightseeing companies that also allow pets onboard, so strap Fido or Garfield in a life jacket and break out your sunblock. The open water is calling you.