Southwest Airline Pet Policy: Fees, Carriers, and Cabin Rules

As of September 2026, the Southwest airline pet policy lets small vaccinated domestic cats and dogs (age 8+ weeks) fly in the cabin only for $125 per carrier one-way on U.S. mainland flights ($35 between Hawaiian Islands), per Southwest Airlines’ Optional Travel Charges and Contract of Carriage. Limit: one carrier per passenger (up to two same-species pets), six carriers per flight; no cargo, no international, no continental U.S.–Hawaii pets.

The Southwest airline pet policy is Southwest Airlines’ published cabin-pet rule set for small domestic cats and dogs. It is not a government travel document, not an EU pet passport, and not the same as Animal Passport, a digital muzzle-biometric livestock identity tool that binds owner, breed, age estimate, body condition, and vaccination history to an animal.

What the Southwest airline pet policy allows

Southwest Airlines states on its Pet Policy help page that it welcomes small, vaccinated domestic cats and dogs in an appropriate pet carrier in the cabin on domestic flights, that pets must be at least eight weeks old, that no pets are transported in the cargo compartment, and that Unaccompanied Minors cannot travel with a pet. The Southwest Airlines Contract of Carriage (Passenger) restates the same core limits: one pet carrier per passenger, up to two animals of the same species in that carrier, and a flight-level limit of six pet carriers accepted on a first-come, first-served basis.

Species beyond domestic cats and dogs are not covered by the cabin pet program described in those Southwest sources. Emotional support, therapy, and in-training animals are not treated as service animals under Southwest’s service-dog guidance published for travelers with disabilities; they may only travel if they qualify under the pet policy. Fully trained service dogs for qualified individuals with disabilities follow separate U.S. Department of Transportation documentation rules and are not charged the Pet Fare described for cabin pets.

Southwest pet fees (as of September 2026)

Southwest Airlines lists Pet Fare on its Optional Travel Charges page as a one-way carry-on pet charge of $125 per pet carrier for U.S. mainland travel and $35 per pet carrier between Hawaiian Islands. Footnote language on that page states that Southwest accepts small vaccinated domestic cats and dogs as pets, that all in-cabin pets must travel in an appropriate carrier, that each pet carrier counts as a carry-on or personal item, and that Pet Fare is subject to change at any time.

The same Optional Travel Charges page lists a ticket-counter pet carrier for purchase at $58 per carrier. Southwest’s Pet Policy page states that Pet Fare must be paid at the Southwest ticket counter with accepted credit cards and that the Pet Fare is refundable if you cancel your reservation. The Contract of Carriage adds that pet reservations can only be booked by calling Southwest, that the pet must be checked in at the airport ticket counter, and that the fare must be paid before you proceed to the departure gate.

Carrier size and under-seat rules

Southwest’s “What type of pet carrier can I bring?” help page requires carriers that are specifically designed as pet carriers, leak-proof, and well ventilated. Other (non–Southwest-sold) carriers may not exceed 18 inches long × 10.5 inches wide × 10 inches high. Southwest’s own ticket-counter pet carrier is listed at 15″ × 10″ × 10″. The cat or dog—including head and tail—must stay completely inside the carrier and must be able to stand up and move around with ease.

The Contract of Carriage requires the carrier to fit under the seat in front of the passenger for the entire flight and bars passengers with pets from exit-row seats or seats with no forward under-seat stowage. Southwest’s onboard expectations page adds that pets must never occupy a passenger seat and may not be located in an exit row or the first row (bulkhead). Soft-sided carriers are recommended because under-seat space varies by seat type; aisle seats can be more limited.

Your pet carrier counts as either your carry-on bag or your personal item, according to both the Acceptable Pet Carriers page and Southwest’s Carryon and Personal Item Policy. You may board with a pet carrier plus a personal item, or a pet carrier plus a regular-size carry-on—but not a full carry-on, personal item, and pet carrier as three free cabin items.

How to book a pet on Southwest: numbered steps

1. Confirm the itinerary is pet-eligible. Pets are not accepted on international itineraries or between the continental United States and Hawaii, per the Contract of Carriage and Destination Requirements page. Pets are accepted on flights between Hawaiian Islands, subject to state entry rules if you are arriving from outside Hawaii.
2. Book your own ticket first, then call Southwest to add the pet reservation. The Contract of Carriage states pet reservations can only be booked by calling Southwest; space is limited to six carriers per flight.
3. Choose a compliant carrier that meets the 18″ × 10.5″ × 10″ maximum (or buy Southwest’s 15″ × 10″ × 10″ carrier) and that lets your pet stand and turn easily.
4. Arrive at the airport ticket counter to check in the pet and pay the Pet Fare before going to the gate, as required by the Contract of Carriage and airport expectations page.
5. Clear security with the pet out of the carrier while the carrier is X-rayed; Southwest’s airport expectations page states you hold your pet through screening and that carriers may be searched.
6. Keep the pet fully inside the carrier in the gate area, during boarding and deplaning, and for the entire flight, with the carrier stowed under the seat.

Destination limits: Hawaii, Puerto Rico, and international

Southwest’s Destination Requirements page states that pets are not allowed on flights to or from Hawaii, that pets are accepted on flights between Hawaiian Islands, and that pets are not allowed on international flights or any itinerary that includes an international flight. The Contract of Carriage separately states that no pets are accepted on itineraries between the continental United States and Hawaii and that no pets will be accepted on international itineraries.

Hawaii’s rabies-free status is enforced by the State of Hawaii Department of Agriculture and Biosecurity (Animal Industry Division / Animal Quarantine). The state’s Animal Quarantine Information Page explains that all dogs and cats must comply with Hawai‘i import requirements regardless of age or purpose, and that Chapter 4-29 Hawaii Administrative Rules governs importation of dogs, cats, and other carnivores. Direct Airport Release and related programs involve microchip identification, rabies vaccination timing, FAVN antibody testing, waiting periods, fees, and document submission deadlines—rules that apply when an animal is entering Hawai‘i from outside the state. Because Southwest does not accept pets on continental United States–Hawaii itineraries, those state entry programs are primarily relevant if you use another carrier for entry or if you move pets between Hawaiian islands under separate airline and state procedures. Always verify current Hawaii Department of Agriculture and Biosecurity requirements before travel.

For Puerto Rico, Southwest’s Destination Requirements and Pet Policy pages state that specific requirements may apply. The airline does not publish a full Puerto Rico checklist on those pages; travelers should confirm destination agriculture and health rules before booking.

Federal Animal Welfare Act context (cabin vs. cargo)

The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) explains that transportation of pets that remain in the custody of their owners is not regulated under the Animal Welfare Act (AWA)—including pets that travel in the aircraft cabin with their owner or the owner’s unpaid designee. APHIS last modified that guidance page on April 17, 2026. By contrast, airlines that take custody of covered animals for cargo transport “for hire” are regulated under the AWA. Because Southwest’s Contract of Carriage states that Southwest will not transport pets in cargo compartments, Southwest cabin pets sit in the owner-custody category for AWA purposes—while airline contract terms, TSA screening, and destination laws still apply.

USDA APHIS: “Transportation of pets that remain in the custody of their owners is not regulated under the AWA,” including cabin travel with the owner. Other federal or state requirements may still apply.

Airport and onboard behavior expectations

Southwest’s airport and onboard pet pages list disruptive behaviors that can lead to denied boarding, including scratching, excessive whining or barking, growling, biting, jumping, lunging, and urinating or defecating in the cabin or gate area. The Contract of Carriage requires pets to be healthy, harmless, inoffensive, odorless, and not needing attention during the flight; it also states that oxygen will not be administered to pets and that an oxygen mask will not be available for the pet in an emergency. Southwest assumes no liability for the health or wellbeing of carry-on pets, according to that contract language.

Pet relief areas exist at airports Southwest serves, but the airport expectations page warns that Southwest will not hold a flight for a relief-area visit. Checked pet strollers are subject to standard checked-bag fees, and Southwest does not assume liability for damage to pet strollers.

Animal Passport vs. airline pet rules (do not confuse them)

Readers searching “southwest airline pet policy” sometimes also ask about “pet passports.” Those are different systems:

• Southwest / airline pet rules govern whether a small dog or cat may board a specific flight, in what carrier, at what fee, and on which routes.
• Government travel documents (for example, destination health certificates, Hawaii quarantine paperwork, or—where applicable—an EU pet passport under the European Union pet travel scheme) are issued or defined by public authorities, not by Animal Passport.
• Animal Passport is a digital animal and livestock passport that uses muzzle biometrics (a nose print unique like a fingerprint). Capture is phone-based. A record can bind owner, breed, estimated age, body condition, and vaccination history. Age can be estimated from a dental photograph with a confidence score, and body condition can be scored 1–5 from a side-profile photo. In August 2025, the product was used in livestock flood rescue in Pakistan so farmers could reclaim animals after paper tags washed away. More field notes appear on the Animal Passport blog.

Animal Passport does not replace Southwest’s Pet Fare, does not authorize cabin boarding, and is not a government-issued airline travel document. Keep vaccination and ownership records organized for your own planning—airline acceptance still depends on Southwest’s published policy on the day you fly.

Practical checklist before you call Southwest

• Confirm species (cat or dog only), age (≥ 8 weeks), and that your pet fits a compliant under-seat carrier with room to stand and turn.
• Verify the route is not international and not continental United States ↔ Hawaii.
• Budget $125 each way per carrier on mainland itineraries ($35 interisland Hawaii), paid at the ticket counter.
• Plan for one carrier per ticketed adult; unaccompanied minors cannot bring pets.
• Reserve early—only six pet carriers per flight under the Contract of Carriage.
• Bring current vaccination records in case agents ask; Southwest’s Pet Policy requires vaccinated pets.
• Skip exit rows and bulkhead seats; choose a seat with under-seat stowage.

Policies and fees change. Re-check Southwest Airlines’ Pet Policy, Optional Travel Charges, Acceptable Pet Carriers, Destination Requirements, and the current Contract of Carriage before you travel. For identity and health-history recordkeeping that is separate from airline boarding rules, see animalpassport.co.