Planning a trip with a four-legged companion can feel a bit like organizing a small expedition. There are crates to measure, nerves to soothe, and a whole list of rules to check off before even heading to the airport. For those looking to fly with a cat or a dog, the Southwest Airlines Pet Policy is generally considered one of the more friendly and straightforward options in the skies.

Southwest has built a reputation on being the "LUV" airline, and that extends to the furry members of the family. However, flying with a pet isn't as simple as just showing up at the gate. From reservation limits to carrier dimensions and specific behavior expectations, there is a lot to keep track of to ensure that nobody gets turned away at the ticket counter.

The Basics: Who Can Fly?

Not every animal is invited to the party. Southwest keeps things simple by limiting in-cabin travel to small, vaccinated domestic cats and dogs. If you have a pet bird, a hamster, or a more "exotic" companion, you’ll need to find an alternative way to get them to your destination.

The age of the pet is also a major factor. To board a flight, puppies and kittens must be at least eight weeks old. This is a standard safety measure, as very young animals are more susceptible to the stresses of pressurized cabins and temperature fluctuations. It’s always a good idea to have a quick chat with a vet before booking, especially if the pet has never traveled before or has underlying health issues like respiratory problems.

Domestic vs. International Flights

One of the most important "fine print" details of the Southwest Airlines Pet Policy involves where you can actually go. Pets are welcome on domestic flights within the contiguous United States. This includes flights between the Hawaiian Islands and travel to Puerto Rico (though Puerto Rico has its own set of vaccination and paperwork requirements).

However, if the itinerary includes an international destination—like Mexico, the Caribbean, or Central America—the pet will have to stay home. Southwest does not allow pets on international flights, nor do they allow them on flights traveling to or from Hawaii from the mainland. This is largely due to the complex quarantine laws and agricultural regulations in those regions.

Making a Reservation: Don't Wait Until the Last Minute

Space for pets is limited on every flight. Southwest typically allows only six pet carriers per flight, though they may occasionally allow more under certain circumstances. Because these spots are first-come, first-served, it’s best to book the pet’s spot as soon as the human tickets are purchased.

To add a pet to a reservation, you have to call Southwest directly or handle it at the ticket counter. You cannot currently add a pet through the standard online booking flow like you would a suitcase.

The Cost of a Pet Fare

Traveling with a pet isn't free. The current Pet Fare is $125 each way per pet carrier for most domestic flights. If you are flying between the Hawaiian Islands, the fee is significantly lower at $35 each way.

It is worth noting that these fees are non-refundable unless the flight is canceled. If you decide to leave the pet at home last minute, you likely won't get that fee back. The payment is handled at the airport ticket counter on the day of travel, so there is no need to pay over the phone when making the initial reservation.

Choosing the Right Pet Carrier

The carrier is the pet’s "seat" for the duration of the journey. Since the carrier must fit under the seat in front of you, the dimensions are strict.

Size Requirements

Southwest allows both soft-sided and hard-sided carriers, but most frequent pet travelers recommend soft-sided ones because they have a little bit of "give" when squeezing under a seat. The maximum dimensions for a pet carrier are:

• 18.5” long x 8.5” high x 13.5” wide

If the carrier is too tall or too wide to fit under the seat, the airline will not allow the pet to board. The animal must be able to stand up, turn around, and lie down comfortably inside the carrier. If the pet looks cramped or can’t move, the gate agent has the discretion to deny boarding for the animal's safety.

Carrier Logistics

Under the Southwest Airlines Pet Policy, the pet carrier counts as either your personal item or your carry-on bag. This means if you bring a pet, you can only bring one other bag (either a suitcase for the overhead bin or a small purse/backpack).

You can put two of the same species (two cats or two dogs) in a single carrier as long as they are small enough to fit comfortably and stay under the weight limits. However, you cannot put a cat and a dog in the same bag—that’s a recipe for a very long, very loud flight.

At the Airport: Checking In and Security

When traveling with a pet, the "curbside check-in" or "mobile boarding pass" life doesn't quite apply. You need to visit the airport ticket counter to pay the Pet Fare and get a special tag for the carrier.

Passing Through TSA

Security is often the most stressful part of the day. You cannot send your pet through the X-ray machine. Instead, you will need to:

1. Remove the pet from the carrier.

2. Send the empty carrier through the X-ray.

3. Carry the pet through the metal detector or walk-through scanner.

It is highly recommended to have the pet on a harness and leash during this process. Airports are loud, busy, and full of strange smells; even the most well-behaved dog might try to bolt if they get spooked by a sudden noise.

Waiting at the Gate

Once you’re through security, the pet must remain in the carrier at all times. This includes the gate area and the jet bridge. While it’s tempting to let them out for a quick cuddle, Southwest is strict about this rule. Most airports now have "Pet Relief Areas" located past security. It is a great idea to find these and give the pet a final chance to stretch their legs and use the bathroom before boarding.

Boarding and the Onboard Experience

Starting in early 2026, Southwest is shifting toward assigned seating. This is a big change from their historic "open seating" model. For pet owners, this actually makes things a little easier to plan.

Where to Sit

When choosing a seat with a pet, keep these rules in mind:

• No Exit Rows: Passengers with pets are never allowed to sit in an exit row.

• No Bulkhead Seats: You cannot sit in the very first row (the bulkhead) because there is no seat in front of you to stow the carrier under.

• Under the Seat: The carrier must stay under the seat for the entire flight. You cannot hold the pet in your lap, even if they are crying or the "Fasten Seatbelt" sign is off.

Behavior Matters

A pet that is barking incessantly, growling at other passengers, or emitting a strong odor can be removed from the flight. While a little whimpering is expected, disruptive behavior can lead to a ban on future travel. Many owners find that "test driving" the carrier at home weeks before the flight helps the pet feel more secure and less likely to fuss during the trip.

Summary of Fees and Rules

Preparing for the Flight: Pro-Tips

Traveling is exhausting for humans, but for a pet, it’s a total sensory overload. To make the journey easier on everyone, consider these small adjustments:

• Limit Food: Try not to feed the pet a large meal right before the flight. A full stomach plus altitude can lead to motion sickness.

• Hydration: Offer water right before the flight, but be mindful of the lack of "restrooms" once you're in the air.

• Familiar Smells: Put a t-shirt you’ve recently worn inside the carrier. Your scent can be incredibly calming for an anxious pet.

• Temperature Control: Airplanes can get chilly. A small, thin blanket inside the carrier can help keep them cozy.

The Southwest Airlines Pet Policy is designed to keep pets safe while ensuring the comfort of other passengers. As long as the carrier fits and the pet is healthy, it’s one of the most accessible ways to travel with a furry friend. Just remember to book early, keep the carrier under the seat, and maybe bring a few extra treats for a job well done.