Southwest Dog Policy 2026: Fees, Carrier Rules & Requirements

Southwest Airlines' dog policy allows small, vaccinated dogs to travel in the cabin — inside an approved carrier stowed under the seat — for $125 per pet carrier each way on U.S. mainland flights, according to Southwest's official Optional Travel Charges page (Southwest Airlines, 2026). Pets never travel as cargo or checked baggage. Only six pet carriers are permitted per flight, and Southwest recommends booking a pet reservation by phone in advance. Trained service dogs fly free with a completed Department of Transportation form. This guide from Animal Passport walks through Southwest's official rules, current as of August 2026, and explains how they differ from unrelated concepts like pet passports.

What Is Southwest's Dog Policy?

Southwest Airlines' dog policy is the airline's set of rules governing which dogs may fly, where they can go, what they must travel in, and what it costs. Southwest classifies dogs as either pets (which pay a fee and must fit in an approved carrier) or trained service dogs (which fly free under federal disability-rights rules). According to Southwest's Help Center pet policy article, the airline "permits small, vaccinated domestic cats and dogs" in cabin carriers on domestic flights only, and pets must be at least eight weeks old (Southwest Airlines, 2026).

Southwest does not offer a cargo-hold pet program the way some legacy carriers do. If a dog cannot fit comfortably in an under-seat carrier, it cannot fly with Southwest as a standard pet.

Southwest Dog Travel Fees (2026)

Southwest publishes its pet fees on its official Optional Travel Charges page. As of August 2026, the fees are:

Each ticketed passenger may bring one pet carrier, and that single carrier may hold up to two cats or dogs of the same species, per Southwest's official pet policy article (Southwest Airlines, 2026). The pet fee applies per carrier, not per animal, so two small dogs sharing one carrier still pay a single fee.

Carrier Requirements for Dogs on Southwest

Southwest requires pets to stay inside their carrier at all times in the gate area, during boarding and deplaning, and for the full duration of the flight (Southwest Airlines Help Center, 2026). Key carrier requirements include:

• The carrier must fit completely under the seat in front of the passenger.
• The dog must be able to stand up and turn around inside the carrier with ease.
• Southwest's own branded carrier, sized 17" (L) x 10" (W) x 9.5" (H), is always accepted.
• Soft-sided carriers from other brands are generally accepted if they meet the under-seat dimension limit.
• The carrier counts as the passenger's one carry-on or personal item allowance.

Because Southwest boards without assigned seats, families flying with a dog often board early using the airline's preboard process for passengers who need extra time, though Southwest's pet policy article notes this is handled case by case at the gate.

Behavioral Standards

Southwest's Help Center states that pets showing disruptive behavior — including scratching, excessive noise, growling, biting, jumping, lunging, or eliminating in the cabin or gate area — may be denied boarding (Southwest Airlines, 2026). Gate agents make this determination at check-in or boarding.

How to Book a Pet Reservation on Southwest

Southwest's Help Center recommends booking pet travel in advance because space is limited to six carriers per flight. The general process is:

1. Book your own ticket first, either online or by phone.
2. Call Southwest at 800-I-FLY-SWA (800-435-9792) to add the pet reservation, since pet carriers cannot be added through the standard online booking flow.
3. Provide your dog's name, breed, and weight to the agent.
4. Pay the pet fare, which Southwest notes is refundable if you ultimately don't travel with your pet.
5. Arrive at the airport with your dog secured in an approved carrier and be prepared to keep it there through security, the gate area, and the flight.

Which Dogs Are Eligible to Fly with Southwest?

Southwest's dog policy limits in-cabin pet travel to small, vaccinated domestic dogs at least eight weeks old (Southwest Airlines, 2026). The airline's published materials do not list breed-specific restrictions, but size is the controlling factor: if the dog cannot stand, turn around, and lie down inside an under-seat carrier, it does not qualify as a cabin pet.

Southwest does not itself set rabies-vaccination or health-certificate rules; those come from the destination state or territory. The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) explains that APHIS "doesn't regulate the interstate movement of pets by their owners" — domestic requirements such as proof of rabies vaccination or a certificate of veterinary inspection are set by each receiving state (USDA APHIS, Take a Pet From One U.S. State or Territory to Another). Because those rules vary, owners should confirm requirements with their destination state before flying.

Service Dogs vs. Emotional Support Animals on Southwest

Southwest's dog policy treats trained service dogs very differently from pets or emotional support animals. Under the U.S. Department of Transportation's Traveling by Air with Service Animals final rule, effective January 2021, airlines may define a service animal as a dog individually trained to do work or perform tasks for a person with a disability, and airlines may treat emotional support animals as ordinary pets subject to pet fees (U.S. Department of Transportation, 2020).

To fly a trained service dog for free, Southwest requires a completed DOT Service Animal Air Transportation Form, dated on or after the ticket purchase date, at check-in (Southwest Airlines, 2026). Southwest explicitly states that a vest, harness, ID card, or registration certificate is not accepted as a substitute for this form. Service dogs must be harnessed, leashed, or tethered at all times and must not occupy a seat, block an aisle, or extend into another passenger's space.

Southwest Pet vs. Service Dog: Quick Comparison

Destination Restrictions: Hawaii, Puerto Rico, and International Flights

Southwest's Help Center destination-information article states that pets are not allowed on flights to or from Hawaii from the mainland, but they are accepted on flights between Hawaiian Islands for $35 each way (Southwest Airlines, 2026). Travelers headed to Hawaii should also check Hawaii's Department of Agriculture rules separately, since the state maintains its own animal-quarantine program independent of the airline.

For Puerto Rico, Southwest points travelers to USDA guidance on entry requirements, since regulations can differ from mainland U.S. states. Southwest's policy is unambiguous on one point: animals cannot travel on any international flight or itinerary that includes an international leg. Southwest is a domestic-only pet carrier.

Do You Need a "Pet Passport" to Fly a Dog on Southwest?

No. Southwest's dog policy does not require anything called a pet passport. That term most often refers to the European Union's pet travel scheme, in which an EU-issued pet passport documents a microchip, rabies vaccination, and veterinary sign-off for animals moving within the EU and, historically, between the UK and EU under the PETS framework. Those documents are issued by accredited veterinarians under government animal-health rules and have no bearing on a domestic U.S. flight with Southwest.

Separately, Animal Passport is a digital identity product that uses phone-based muzzle-biometric capture — a nose print, which is unique to each animal much like a human fingerprint — to bind an owner, breed, estimated age, and vaccination history to a single record. It also produces a dental-photo-based age estimate with a confidence score and a 1–5 body condition score from a side-profile photo. This technology was used in livestock flood rescue efforts in Pakistan in August 2025, helping farmers reclaim animals after paper ear tags washed away. It is a useful tool for maintaining a portable, tamper-resistant identity and health record for an animal — but it is not a government-issued travel document, not a veterinary diagnosis, and not something Southwest, the DOT, or USDA APHIS currently requires or recognizes for boarding a flight. Owners flying with dogs should still follow Southwest's official carrier and fee rules above; a biometric ID record is a complement to good recordkeeping, not a substitute for airline paperwork. For more on how digital animal identification works in practice, see the Animal Passport blog.

Common Mistakes That Get Dogs Denied Boarding

• Booking the flight without calling to add the pet. Southwest's online system does not always allow pet reservations to be added after the fact, and only six carriers are allowed per flight.
• Using an oversized carrier. If the carrier does not fit fully under the seat, gate agents can deny boarding.
• Assuming Hawaii mainland flights allow pets. They do not; only inter-island Hawaii routes accept pets.
• Confusing an emotional support animal with a service dog. Since the 2020 DOT rule, emotional support animals are treated as pets and charged the standard pet fee (U.S. Department of Transportation, 2020).
• Arriving without the DOT form for a service dog. Southwest will not accept a vest or ID card as a substitute.

Frequently Asked Questions

Does Southwest allow dogs in the cabin?

Yes. Southwest's dog policy allows small, vaccinated dogs at least eight weeks old to travel in the cabin inside an approved under-seat carrier on domestic U.S. flights (Southwest Airlines, 2026).

How much does it cost to fly a dog on Southwest Airlines?

Southwest charges $125 per pet carrier each way for U.S. mainland flights, and $35 each way for flights between Hawaiian Islands, per Southwest's Optional Travel Charges page (2026). The fee is refundable if you don't ultimately travel with your pet.

What size carrier does Southwest require for a dog?

The carrier must fit fully under the seat in front of the passenger, and the dog must be able to stand and turn around inside it. Southwest's own branded carrier measures 17" x 10" x 9.5" and is always accepted (Southwest Airlines, 2026).

Can I bring my dog to Hawaii on Southwest?

Not on flights to or from the mainland — Southwest does not allow pets on those routes. Pets are permitted on flights between Hawaiian Islands for $35 each way, and travelers should also check Hawaii Department of Agriculture requirements separately (Southwest Airlines, 2026).

Do service dogs fly free on Southwest?

Yes. Trained service dogs that meet the U.S. Department of Transportation's definition fly without a fee, provided the handler submits a completed DOT Service Animal Air Transportation Form at check-in (Southwest Airlines, 2026; U.S. Department of Transportation, 2020).

Does Southwest require a pet passport for dogs?

No. Southwest does not require a pet passport of any kind for domestic flights. "Pet passport" typically refers to EU/UK travel documents, which apply to international pet travel abroad, not U.S. domestic airline rules.

How many pets can I bring on one Southwest flight?

Each ticketed passenger may bring one carrier holding up to two dogs or cats of the same species, and Southwest limits each flight to six total pet carriers (Southwest Airlines, 2026).

Can emotional support animals fly free on Southwest?

No. Since the DOT's 2020 final rule, airlines including Southwest may treat emotional support animals as regular pets, meaning they must fit in an approved carrier and pay the standard pet fee (U.S. Department of Transportation, 2020).