If you’re planning a trip and don’t want to leave your furry friend behind, you’re not alone. Thousands of pet owners fly with their cats and dogs every year — and Southwest Airlines is one of the more straightforward options when it comes to the Southwest Airlines pet policy. No hidden surprises, no complicated cargo processes. Just simple rules you can follow to make the trip smooth for both you and your pet.

This guide covers everything — fees, carrier size, booking steps, breed rules, and what to expect at the airport. Read it once and you’ll know exactly what to do before your flight day.

What Is the Southwest Airlines Pet Policy?

The Southwest Airlines pet policy allows small, vaccinated domestic dogs and cats to fly inside the cabin with their owners. Your pet travels under the seat in front of you — not in the cargo hold, not in a separate area.

This is actually great news for pet owners. Flying your pet in-cabin is far less stressful for the animal compared to cargo travel. They stay with you, they can hear your voice, and they don’t have to deal with the noise and temperature changes of the baggage area.

There are a few basic things Southwest requires:

• Only dogs and cats are allowed — no other animals
• Pets must be at least 8 weeks old
• They must be vaccinated
• They must travel in an approved carrier that fits under the seat
• Only domestic flights are allowed — no international pet travel

Southwest does not allow pets in the cargo hold at all. So if your pet is too large for a cabin carrier, unfortunately Southwest is not the right airline for your trip.

Southwest Airlines Pet Fee: How Much Does It Cost?

Let’s talk money first, because this is often the first question people have.

The Southwest Airlines pet fee is $125 per pet carrier, each way. So if you’re flying round-trip, that’s $250 total.

For travel between Hawaiian islands, the fee is lower — just $35 per carrier, each way.

A few things to keep in mind about the pet fee:

• You pay it at the airport check-in counter, not online during booking
• You must pay with a credit or debit card — Southwest gift cards, LUV Vouchers, and flight credits are not accepted for pet fees
• The fee is refundable if your flight gets canceled or you need to change plans
• The fee is per carrier, not per pet — so if two small pets share one carrier, you only pay once

Fees can change, so it’s always worth confirming on Southwest’s official website before you travel.

What Pets Are Allowed on Southwest Airlines?

The Southwest Airlines pet policy is specific about which animals can fly. Only small domestic dogs and cats are permitted. That’s it.

Sorry rabbit lovers, bird enthusiasts, and reptile owners — Southwest does not allow any other type of pet in the cabin. No hamsters, no ferrets, no fish, no exotic animals.

Age and Health Requirements

Your pet must be:

• At least 8 weeks old (about 2 months)
• Vaccinated against common diseases
• In good health — Southwest staff can deny boarding to a pet that appears sick or unwell

You may be asked to show proof of vaccination, though it’s not always required. It’s still a good idea to carry your pet’s vaccination records with you just in case.

Behavioral Requirements

Southwest also expects pets to be well-behaved during the flight. A pet that is aggressive, excessively loud, or disruptive can be denied boarding. Your pet needs to stay inside the carrier at all times — from the moment you board until the plane lands and you exit the gate area.

Southwest Airlines Pet Carrier Rules: Size and Type

This is one of the most important parts of the Southwest Airlines pet policy. If your carrier doesn’t fit the requirements, you won’t be boarding with your pet.

Carrier Size

The carrier must fit comfortably under the seat in front of you. Southwest’s approved maximum carrier dimensions are:

18.5 inches (L) x 13.5 inches (W) x 8.5 inches (H)

These dimensions apply to both hard-sided and soft-sided carriers. Soft-sided carriers are more flexible and tend to fit more easily under seats because they can compress slightly.

What Makes a Carrier Acceptable?

Your carrier must be:

• Leak-proof — accidents happen, and the carrier needs to contain them
• Well-ventilated — mesh panels or vents so your pet can breathe comfortably
• Secure — no way for your pet to escape during the flight
• Comfortable enough for your pet to stand up, turn around, and lie down inside

If your pet can’t move around inside the carrier, it’s too small. Southwest takes animal comfort seriously.

How Many Pets Per Carrier?

Southwest allows up to two pets of the same species in one carrier — as long as they both fit comfortably and aren’t cramped. So two small cats or two small dogs can share a carrier, but not a cat and a dog together.

Each passenger is allowed one carrier, which counts as either your personal item or carry-on item. Plan accordingly.

How Many Pets Are Allowed Per Flight?

Here’s something a lot of people don’t realize until it’s too late: Southwest limits the number of pets per flight to 6 carriers. This number is strictly first-come, first-served.

If 6 people have already reserved pet space on your flight, you won’t be able to bring your pet on that flight. This is why booking early is so important when you’re traveling with a pet.

In some cases the limit may be slightly higher or lower depending on the specific flight, but 6 is the general rule.

How to Book a Pet on Southwest Airlines

You cannot add a pet to your reservation online. Southwest requires you to call them directly.

Here’s how to do it:

1. Book your own flight — you can do this online as normal
2. Call Southwest at 1-800-I-FLY-SWA (1-800-435-9792)
3. Let them know you’re traveling with a pet and request pet space on your flight
4. They will confirm availability and note your reservation

Do this as soon as possible after booking your own ticket. With only 6 pet spots per flight, they fill up fast — especially on popular routes and holiday travel periods.

What to Expect at the Airport

When you arrive at the airport, you must check in at the ticket counter — you cannot use online check-in or the app when traveling with a pet. A Southwest agent will inspect your carrier to make sure it meets the requirements and process your pet fee payment.

After check-in, your pet stays with you in the carrier through security and during the flight.

A few airport tips:

• Give your pet a bathroom break before entering the terminal — once inside, there aren’t many spots, and pets are not allowed to relieve themselves in the gate area or cabin
• Don’t feed your pet a large meal right before the flight to avoid an upset stomach
• Bring a small water dispenser or ice cubes your pet can lick during the trip
• Arrive a little earlier than usual to allow time for the check-in process

Southwest Airlines Pet Policy for Hawaii and Puerto Rico

Flights to/from Hawaii from the mainland: Southwest does not allow pets on these flights. So if you’re flying from the U.S. mainland to Hawaii, you cannot bring your pet in-cabin on Southwest.

Flights between Hawaiian islands: Pets are allowed on inter-island Southwest flights. The fee is $35 per carrier, each way — much lower than the mainland fee.

Flights to Puerto Rico: Pets are allowed, but there may be additional entry requirements for animals entering Puerto Rico. You may need an official interstate health certificate from a USDA-accredited veterinarian. Check Puerto Rico’s entry requirements before your trip.

Service Animals vs. Pets: What’s the Difference?

Under the Southwest Airlines pet policy, trained service animals are treated differently from regular pets.

Service dogs that are trained to assist passengers with physical or medical disabilities can fly free of charge. They don’t need to be in a carrier — they can sit at the handler’s feet or in their lap. Southwest follows the U.S. Department of Transportation (DOT) rules for service animals.

To bring a service dog, you may need to submit a DOT Service Animal Air Transportation Form at least 48 hours before your flight.

Emotional support animals (ESAs) are a different story. Southwest no longer recognizes ESAs as service animals. If you travel with an emotional support animal, it will be treated as a regular pet under the standard pet policy — meaning carrier requirements, fees, and all the same rules apply.

What Pets Are NOT Allowed on Southwest?

To be clear, the Southwest Airlines pet policy does not allow:

• Large dogs or cats that don’t fit in the carrier dimensions
• Any pet in the cargo hold
• Pets on international flights
• Animals other than domestic dogs and cats
• Pets traveling with unaccompanied minors

If your dog is too big to fit in an approved carrier, you’ll need to look at other airlines that allow larger pets or offer cargo pet travel options.

Tips for a Stress-Free Flight With Your Pet

Traveling with a pet takes a little extra preparation. Here are some practical tips:

Before the flight:

• Buy an airline-approved carrier well in advance and let your pet get used to it at home. Leave it open with a blanket or toy inside so they see it as a safe space.
• Visit your vet before the trip, especially if it’s your pet’s first flight. Get a clean bill of health and update any vaccinations.
• Call Southwest as early as possible to reserve your pet’s spot.

Day of travel:

• Exercise your pet before leaving for the airport to help burn off energy
• Arrive early to allow time for check-in
• Stay calm — pets pick up on your stress, so the more relaxed you are, the more relaxed they’ll be

During the flight:

• Keep your carrier under the seat — never place it in the overhead bin
• Talk softly to your pet if they seem anxious
• Don’t take your pet out of the carrier during the flight

Frequently Asked Questions About the Southwest Airlines Pet Policy

Can I bring my dog on Southwest Airlines? Yes, small vaccinated dogs at least 8 weeks old can fly in-cabin on domestic Southwest flights in an approved carrier.

How much does it cost to bring a pet on Southwest? The fee is $125 per carrier each way on domestic flights, and $35 per carrier each way between Hawaiian islands.

Can my pet fly in the cargo hold on Southwest? No. Southwest does not offer cargo pet travel. Pets must fly in-cabin only.

Can I book my pet online? No. You must call Southwest at 1-800-435-9792 to reserve a spot for your pet.

Does Southwest allow emotional support animals? No. ESAs are no longer given special status and must follow the regular pet policy.

What size carrier does Southwest allow? Maximum dimensions are 18.5″ L x 13.5″ W x 8.5″ H.

How many pets are allowed per flight? Generally 6 carriers per flight, on a first-come, first-served basis.

Final Thoughts

The Southwest Airlines pet policy is one of the cleaner and more pet-friendly policies among major U.S. carriers — as long as your pet is small enough to travel in-cabin. The rules are clear, the fees are reasonable, and the process is simple once you know the steps.

The two biggest things to remember: call early to reserve your spot, and make sure your carrier meets the size requirements. Do those two things, and your trip with your pet should go smoothly.

Whether you’re taking a short hop or a longer cross-country trip, Southwest makes it possible to bring your four-legged family member along — and that’s what matters most.