Southwest Dog Flying Rules for Cabin Dogs

Southwest dog flying means a small, vaccinated domestic dog at least eight weeks old travels in the cabin on Southwest Airlines, not in cargo. As of September 2026, Southwest lists a one-way pet fare of $125 per carrier on the U.S. mainland and $35 between the Hawaiian Islands. The airline bars international trips and continental United States–Hawaii flights and caps carriers at six per flight.

Animal Passport published this guide in September 2026. The fee is on Southwest’s Optional Travel Charges page. The six-carrier cap is in the Contract of Carriage, 56th revision, effective July 16, 2026. Those airline rules are not a government pet passport, and they are not the same document as a territory health certificate.

What Southwest dog flying allows

Southwest may accept small vaccinated domestic cats and dogs at least eight weeks old, traveling with a passenger inside a pet carrier. That rule is in the Pets section of the Contract of Carriage. One ticketed passenger may bring one carrier. The carrier may hold up to two animals of the same species, so two small dogs may share a carrier and a dog may not share with a cat. Unaccompanied minors may not travel with a pet.

Southwest reserves the right to limit each flight to six pet carriers and to accept pets first come, first served. A confirmed human ticket does not hold a pet slot. The dog must be healthy, harmless, inoffensive, odorless, and require no attention during the flight. Southwest may refuse a pet it considers incompatible with air travel. Its pet policy lists scratching, excessive whining or barking, growling, biting, jumping, lunging, and urinating or defecating in the cabin or gate area.

The $125 pet fare and the $58 carrier price

As of September 2026, Southwest’s Optional Travel Charges page lists two pet prices that travelers mix up. The one-way carry-on pet charge is $125 per pet carrier on the U.S. mainland and $35 per pet carrier between the Hawaiian Islands. A separate line, under items for purchase at the ticket counter, lists a pet carrier at $58. That $58 figure buys a bag. It does not reserve the dog’s place on the airplane.

Footnote 7 says each pet carrier counts as a carry-on or a personal item and that the pet fare can change at any time. Southwest also says it may amend listed prices. Recheck the fees page before travel.

Pet reservations can only be booked by calling Southwest. The contract requires check-in at the airport ticket counter and payment of the pet fare before the passenger goes to the gate. Southwest’s pet policy says payment is by accepted credit card. If the reservation is canceled, the pet fare is refundable. Denial for behavior or a carrier that will not fit is a separate risk.

Carrier size and the second bag

The Contract of Carriage requires a leak-proof, well-ventilated carrier small enough to fit under the seat in front of the passenger. Head and tail must stay inside the carrier in the gate area, during boarding and deplaning, and for the entire flight. The dog must be able to stand up and move around inside the carrier. Passengers with a pet may not occupy an exit row or a seat with no forward under-seat stowage.

Southwest’s help article on pet carriers publishes dimensions the contract does not print. The airline’s own carrier is listed at 15 inches long, 10 inches wide, and 10 inches high. Other carriers are listed at a maximum of 18 inches long, 10.5 inches wide, and 10 inches high. Southwest recommends a soft-sided carrier because under-seat space varies. The contract still controls: the carrier must fit under the seat, and the dog must be able to stand and move.

The same article says you may board with a pet carrier and a personal item, or a pet carrier and a regular-size carry-on. The carrier uses one of those two slots. It is not a third free bag.

Security screening and the cabin

Pay at the ticket counter before the gate. The dog stays fully inside the carrier from the gate through the flight.

The Transportation Security Administration (TSA) screens pets at the checkpoint. TSA’s pet FAQ says to remove the pet from the carrying case, send the case through the X-ray, keep control with a leash, and remove the leash when carrying the pet through the metal detector. Carriers may be inspected visually or physically. TSA tells travelers to confirm the airline policy before arrival. Do not send the dog through the X-ray.

If the pet becomes ill in flight, the contract says oxygen or other first aid will not be given, and no emergency oxygen mask is provided for the pet. Southwest assumes no liability for the health or wellbeing of carry-on pets.

Southwest will not transport pets in the aircraft cargo compartments.

That sentence is Pets section e.(5) of the July 16, 2026 Contract of Carriage. A dog that cannot stand and turn inside an under-seat carrier cannot be moved to the hold. Many adult dogs cannot fly Southwest at all.

Routes that do not allow a dog

The contract states that no pets are accepted on international itineraries, and section 8 repeats that ban. Southwest’s destination page adds that pets are refused on any itinerary that includes an international flight. A domestic connection on an international ticket is not a workaround.

The contract also states that no pets are accepted on itineraries between the continental United States and Hawaii. The destination page agrees, and it allows a narrower case: pets are accepted on flights between the Hawaiian Islands. The $35 fare is the price for that interisland case. It is not a fare from the mainland to Honolulu.

Puerto Rico is not on that ban list. Southwest’s destination page only says specific requirements may apply. Those requirements are the territory’s, not the pet fare.

Puerto Rico’s health certificate

The Puerto Rico Department of Agriculture document “Health Requirements Governing the Admission of Animals into Puerto Rico,” last modified November 11, 2024, says dogs and cats do not need a department import permit for interstate movement. They do need an official certificate of veterinary inspection signed by an accredited veterinarian in the origin state or territory, valid for 30 days, stating the animal did not come from an area quarantined for rabies.

Dogs and cats over four months old must have been vaccinated against rabies within six months before shipment, must be identified, and must travel with a rabies certificate. The same page requires external-parasite treatment within 72 hours before entry, written on the health certificate, plus a microchip or a collar with a metallic ID tag. An earlier paragraph requires an import permit for animals in general. The dogs-and-cats bullets waive that permit for interstate pets. Confirm with the department if you are unsure. This article is not legal advice.

Southwest’s pet section requires a vaccinated dog. It does not name rabies, a form number, or a 10-day certificate window for an ordinary mainland flight that never enters Puerto Rico.

Hawaii quarantine does not create a Southwest seat

The Hawaii Department of Agriculture states that Hawaii is rabies-free and that every dog and cat must meet import rules. Qualifying animals may use the 5 Day Or Less program, including direct release at Daniel K. Inouye International Airport in Honolulu. Others can be quarantined up to 120 days. Direct release in Honolulu is listed at $185 if documents arrive at least 10 days ahead, and $244 if they do not. The page also requires a 30-day wait after a passing FAVN rabies antibody test and after the latest rabies vaccination.

Those are State of Hawaii entry rules. They do not amend Southwest’s contract. A completed FAVN test or a paid quarantine fee does not put a pet on a Southwest flight from the continental United States to Hawaii. Interisland flights are different: Southwest accepts cabin pets between the islands at the $35 one-way fare.

Pet dogs, emotional support dogs, and service dogs

The Contract of Carriage defines a trained service animal as a dog, regardless of breed, individually trained to do work or perform tasks for a qualified individual with a disability, including a psychiatric disability. Emotional support animals, comfort animals, companionship animals, other species, and service animals in training are not trained service animals. Southwest says it will not carry an animal unless the federal Air Carrier Access Act or U.S. Department of Transportation rules require it.

A qualified passenger’s trained service dog may ride in the cabin at no charge, which the contract ties to 14 CFR § 382.72 through § 382.80. The passenger must provide a completed U.S. Department of Transportation Service Animal Air Transportation Form. Southwest may ask questions and watch the dog’s behavior. An emotional support dog does not get that free seat. If the dog is small enough for the pet rules, it can fly only as a pet, with a phone reservation, the six-carrier cap, and the $125 or $35 fare. A large emotional support dog still cannot go in the hold.

A handler on official business may fly a fully trained law-enforcement or search-and-rescue dog without the pet fare by presenting a mission letter and certification. That exception does not cover a family pet.

How to book

1. Confirm the dog is a small domestic dog, at least eight weeks old, and vaccinated, and that the itinerary has no international flight and no continental-to-Hawaii leg.
2. Use a leak-proof carrier within Southwest’s published maximum of 18 by 10.5 by 10 inches, and confirm the dog can stand and turn inside it.
3. Call Southwest to add the pet. The contract says pet reservations can only be booked by phone. Ask whether the flight is already at six carriers.
4. At the airport, pay the pet fare at the ticket counter with an accepted credit card before going to the gate. Budget $125 each way per carrier on the mainland, or $35 between Hawaiian Islands, and recheck the fees page.
5. At the TSA checkpoint, remove the dog, X-ray the empty carrier, and carry the dog through the metal detector.
6. Keep the dog inside the carrier from the gate onward, and stow the carrier under the seat in front of you, not in an exit row.

Southwest tells Getaways customers to check hotel and rental-car pet rules separately.

Not an Animal Passport or an EU pet passport

Southwest’s cabin rules, a European Union pet passport, the United Kingdom PETS travel scheme, and a private livestock identity file are different instruments. The contract does not treat a biometric record as permission to board. Southwest also does not fly pet dogs internationally, so an export health certificate would not create a Southwest pet booking.

Animal Passport is a digital animal and livestock passport that uses muzzle biometrics. A nose print is unique in the way a fingerprint is unique. Capture is phone-based. The record binds the owner, breed, estimated age, body condition, and vaccination history. Age is estimated from a dental photograph and returned with a confidence score. Body condition is scored from 1 to 5 using a side-profile photo. In August 2025 the record was used in livestock flood rescue in Pakistan so farmers could reclaim animals after paper tags washed away. It is not a veterinary diagnosis, not legal advice, and not a government-issued travel document.

More identity-versus-travel explainers are on the Animal Passport blog. For Southwest, what matters is the phone reservation, the counter payment, and any health certificate the destination itself requires.

Questions about Southwest dog flying

Can I fly my dog on Southwest?

Yes, if the dog is a small vaccinated domestic dog at least eight weeks old, travels in an under-seat carrier, and the flight still has pet space. The July 16, 2026 Contract of Carriage limits carriers to six per flight and refuses pets in cargo, on international itineraries, and between the continental United States and Hawaii.

How much does Southwest charge to fly a dog?

As of September 2026, Southwest lists $125 each way per pet carrier on the U.S. mainland and $35 each way between the Hawaiian Islands. The $58 carrier sold at the ticket counter is a bag, not the flying fee. The fare can change and is paid at the ticket counter.

Does Southwest allow dogs in cargo?

No. The Contract of Carriage states that Southwest will not transport pets in the aircraft cargo compartments. A dog that does not fit under the seat cannot be checked as baggage.

What size carrier can I use?

Southwest’s pet-carrier article lists its own carrier at 15 by 10 by 10 inches and other carriers at a maximum of 18 by 10.5 by 10 inches. The dog, including head and tail, must fit inside, be able to stand and move, and the carrier must stow under the seat in front of you.

Can I take my dog to Hawaii on Southwest?

Not between the continental United States and Hawaii. Quarantine paperwork does not override that ban. Southwest does accept cabin pets on flights between the Hawaiian Islands at the $35 one-way pet fare.

Do emotional support dogs fly free on Southwest?

No. The contract excludes emotional support animals from the trained-service-animal definition. They fly only as pets if they meet the carrier rules and the fare is paid. A trained service dog accompanying a qualified individual with a disability flies at no charge with a completed U.S. Department of Transportation Service Animal Air Transportation Form.

Do I need a health certificate on a mainland Southwest flight?

Southwest requires a vaccinated dog but does not set a certificate form for ordinary mainland flights. Puerto Rico does: the Department of Agriculture requires a certificate of veterinary inspection valid for 30 days, plus rabies and parasite conditions for dogs entering the territory.

Can two dogs share one carrier?

Yes. One passenger may bring one carrier holding up to two animals of the same species. Southwest charges the pet fare per carrier, not per dog. Both dogs must still be able to stand and move inside it.