Flying Animals on Southwest Airlines: Rules, Fees, and Carrier Requirements
Key takeaways
- Southwest Airlines only carries small, vaccinated cats and dogs in the cabin; it does not accept pets as checked baggage or cargo, per Southwest's official pet policy.
- The pet fare is $125 per carrier, each way, on U.S. mainland flights, and $35 per carrier between the Hawaiian Islands, according to Southwest's Optional Travel Charges page.
- Southwest caps pet carriers at six per flight and requires a phone reservation at 1-800-435-9792 in advance — pets cannot be added through the website.
- Southwest does not fly pets to or from Hawaii, or on any itinerary that includes an international segment, per Southwest's official destination-restrictions article.
- Only trained service dogs fly free under the U.S. Department of Transportation's 2021 service animal rule; emotional support animals are booked and charged as regular pets.
- Southwest's own support pages give slightly different carrier dimensions across articles (roughly 18"–18.5" L x 10.5"–13.5" W x 9.5"–10" H); call Southwest to confirm the exact figure before buying a carrier.
- The USDA Animal and Plant Health Inspection Service (APHIS) does not regulate interstate pet travel — health certificate rules for state-to-state trips come from the destination state, not the federal government.
- Animal Passport's biometric muzzle-ID system is a separate livestock identification product; it is not a Southwest travel document, an FAA/DOT form, or a substitute for Southwest's pet health and vaccination requirements.
Flying animals on Southwest Airlines means bringing a small, vaccinated cat or dog into the passenger cabin in an approved carrier for a paid pet fare — Southwest does not transport pets as checked baggage or in the cargo hold. The current pet fare is $125 per carrier, each way, on U.S. mainland routes, and the carrier must fit under the seat in front of you, according to Southwest Airlines' official pet policy and Optional Travel Charges page (Southwest Airlines, 2026).
This guide walks through Southwest's actual rules — sourced directly from Southwest's help center, the U.S. Department of Transportation (DOT), and the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) — plus the questions people search around this keyword: fees, carrier sizes, Hawaii and international restrictions, and service animals versus emotional support animals.
Southwest Airlines Pet Policy: The Core Rules
Southwest's official pet policy states the airline welcomes "small, vaccinated domestic cats and dogs" that travel in-cabin only, on domestic itineraries (Southwest Airlines Support, 2026). Pets must be at least eight weeks old. Each ticketed passenger may bring one carrier, and a single carrier may hold up to two small cats or dogs of the same species, provided both animals fit comfortably and can stand, turn around, and lie down inside.
Pets must stay inside the carrier at all times in the gate area, during boarding, throughout the flight, and during deplaning. Southwest's policy also warns that pets showing disruptive behavior — excessive vocalization, scratching, growling, biting, jumping, or eliminating in the cabin or gate area — may be denied boarding (Southwest Airlines Support, 2026).
How Much Does It Cost to Fly a Pet on Southwest?
According to Southwest's Optional Travel Charges page, the pet fare is:
- $125 per pet carrier, one way, for travel on the U.S. mainland (Southwest Airlines, 2026)
- $35 per pet carrier, one way, for travel between the Hawaiian Islands only (Southwest Airlines, 2026)
- $58 if you need to buy an approved carrier at the ticket counter (Southwest Airlines, 2026)
The pet fare is refundable if you cancel the reservation, and it is paid at the ticket counter with an accepted credit card — not online. Pets do not earn Rapid Rewards points.
How to Book a Pet Reservation
- Call Southwest at 1-800-I-FLY-SWA (1-800-435-9792) as soon as you know your travel dates — pet spots cannot be reserved on southwest.com.
- Confirm your pet meets age, health, and species requirements (small, vaccinated cat or dog, at least 8 weeks old).
- Buy or bring an approved carrier that fits under the seat.
- Arrive early and check in your pet at the ticket counter, where the pet fare is collected.
- Keep your pet in the carrier through security, boarding, the flight, and deplaning.
Southwest allows a maximum of six pet carriers per flight on a strict first-come, first-served basis, so reservations should be made well before departure.
Carrier Size Requirements
Southwest's official carrier-specifications article lists Southwest's own branded carrier at 15" L x 10" W x 10" H and states other approved soft- or hard-sided carriers must not exceed 18" L x 10.5" W x 10" H (Southwest Airlines Support, 2026). Separately, Southwest's general pet-policy pages describe under-seat carrier space as roughly 18.5" L x 13.5" W x 9.5" H depending on aircraft type. Because Southwest's own published figures vary slightly by article and by aircraft, confirm exact under-seat dimensions with a reservations agent before purchasing a carrier.
Whatever the exact number, the carrier must be:
- Leak-proof and well ventilated
- Secure enough to prevent the pet from escaping
- Roomy enough for the pet to stand, turn around, and lie down
- Stowable flat under the seat in front of the passenger
Where Southwest Will Not Fly Pets
Southwest's destination-restrictions article states pets are accepted on flights between the Hawaiian Islands but are not permitted on any flight to or from Hawaii from the U.S. mainland (Southwest Airlines Support, 2026). Southwest also does not allow pets "on international flights or any itinerary that includes an international flight" (Southwest Airlines Support, 2026) — pet travel on Southwest is domestic-only. For Puerto Rico, Southwest directs customers to check USDA guidelines before booking.
Service Animals vs. Emotional Support Animals
Under the U.S. Department of Transportation's Air Carrier Access Act rule, effective January 11, 2021, only a dog "individually trained to do work or perform tasks for the benefit of a qualified individual with a disability" qualifies as a service animal for free travel (U.S. Department of Transportation, 2020). Airlines, including Southwest, may require passengers to submit the DOT Service Animal Air Transportation Form once per round trip. Emotional support animals are no longer recognized as service animals under this rule; Southwest books them — and charges for them — as ordinary pets under its standard pet policy.
Southwest Service Animal Rules at a Glance
| Category | Fee | Where It Travels | Documentation |
|---|---|---|---|
| Small vaccinated cat or dog (pet) | $125 each way (mainland) | Inside an approved carrier, under the seat | None filed with Southwest in advance; owner attests to health/vaccination at check-in |
| Trained service dog | Free | At handler's feet or on lap, out of carrier if trained | DOT Service Animal Air Transportation Form |
| Emotional support animal | Same as pet fare | Inside an approved carrier, under the seat | Treated as a standard pet reservation |
Health Certificates: What the USDA Actually Requires
A common misconception is that a USDA-endorsed health certificate is required to fly a pet domestically on Southwest. It is not, at the federal level. USDA APHIS states plainly that it "doesn't regulate the interstate movement of pets by their owners" — health certificate and vaccination requirements for domestic (state-to-state) pet travel are set by the destination state or territory, not by APHIS (USDA APHIS, 2026). Owners should check with their destination state's animal health office or their veterinarian, since requirements vary by state.
This is different from international pet travel, where APHIS-endorsed export health certificates and country-specific entry rules apply — a process Animal Passport has covered separately in its USDA APHIS pet travel guide. Southwest does not fly pets internationally at all, so that process does not apply to a Southwest pet reservation.
Where the IATA Live Animals Regulations Fit In
The International Air Transport Association (IATA) publishes the Live Animals Regulations (LAR), the global reference standard airlines use for humane transport of animals, with a new edition effective January 1, 2026 (IATA, 2026). IATA also publishes separate guidance specifically for passengers flying with a dog or cat in the cabin, covering carrier design, in-flight welfare, and pre-flight preparation. Southwest's own cabin-only pet policy is consistent with IATA's cabin guidance, though Southwest's specific fees, sizes, and booking process are set by Southwest, not IATA.
Don't Confuse a Southwest Pet Reservation With a "Pet Passport"
Searchers sometimes conflate "flying animals on Southwest Airlines" with formal travel documents like the European Union pet passport. These are unrelated systems. The EU pet passport is an official document, standardized across EU member states, that records a pet's microchip number, rabies vaccination history, and issuing veterinarian, and it is required for dogs, cats, and ferrets moving between EU countries (European Commission, Your Europe portal, 2026). It has no bearing on a Southwest domestic flight in the United States.
Animal Passport, the publisher of this article, makes a separate, unrelated product: a phone-based digital livestock identity system that captures a muzzle (nose print) biometric — unique to each animal, similar to a human fingerprint — along with an owner record, breed, dental-photo age estimate with a confidence score, and a 1–5 body condition score from a side-profile photo. It was used during livestock flood rescue efforts in Pakistan in August 2025 so farmers could reclaim animals after paper ear tags were washed away. Animal Passport is not a government-issued travel document, not an EU pet passport, not a USDA export certificate, and not accepted by Southwest Airlines or any airline as pet travel paperwork. If you are flying a cat or dog on Southwest, follow Southwest's own pet policy and your destination state's or country's official animal health requirements — read more on how Animal Passport's livestock identification technology works at animalpassport.co.
Step-by-Step Checklist Before You Fly
- Confirm your route is fully domestic — Southwest excludes Hawaii-mainland and international itineraries.
- Call 1-800-435-9792 to reserve one of the six pet spots per flight.
- Verify your pet is a cat or dog, at least 8 weeks old, and current on vaccinations.
- Buy or confirm an approved carrier; call Southwest to verify exact under-seat dimensions for your aircraft.
- Check your destination state's health-certificate rules with your veterinarian, since APHIS does not set interstate requirements.
- Arrive early to pay the pet fare and check in at the ticket counter.
- Keep the pet in the carrier for the entire airport and flight experience.
As of September 2026, these are Southwest's published rules; airline policies change without notice, so confirm fees and carrier limits directly with Southwest before booking. For broader background on pet travel paperwork, see Animal Passport's blog.
FAQ
- Can I bring my dog or cat on Southwest Airlines?
- Yes. Southwest Airlines allows small, vaccinated domestic cats and dogs to fly in the cabin, inside an approved carrier under the seat, for a $125 one-way pet fare on U.S. mainland flights (Southwest Airlines, 2026).
- How much does Southwest charge to fly with a pet?
- Southwest's pet fare is $125 per carrier each way on the U.S. mainland and $35 per carrier for flights between the Hawaiian Islands, per Southwest's Optional Travel Charges page (Southwest Airlines, 2026).
- Does Southwest Airlines allow pets as checked baggage or in cargo?
- No. Southwest only carries small cats and dogs in the passenger cabin; it does not accept pets as checked baggage or cargo, according to Southwest's official pet policy.
- Can I fly a pet to Hawaii on Southwest Airlines?
- No. Southwest allows pets on flights between the Hawaiian Islands but does not permit pets on any flight to or from Hawaii from the U.S. mainland, per Southwest's destination-restrictions page (Southwest Airlines Support, 2026).
- How many pets can fly on one Southwest flight?
- Southwest caps pet carriers at six per flight on a first-come, first-served basis, so advance phone reservation at 1-800-435-9792 is required.
- Do service dogs fly free on Southwest Airlines?
- Yes. Under the U.S. Department of Transportation's 2021 service animal rule, only trained service dogs fly free; emotional support animals do not qualify and are booked as paid pets under Southwest's standard pet policy.
- Do I need a USDA health certificate to fly my pet on Southwest domestically?
- Not from the federal government directly. USDA APHIS does not regulate interstate pet travel — health certificate requirements for state-to-state trips are set by the destination state, so check with your vet and that state's animal health office (USDA APHIS, 2026).
- Is Animal Passport the same as a pet travel document for Southwest Airlines?
- No. Animal Passport is a separate biometric livestock identification product using muzzle prints; it is not an airline travel document, a USDA certificate, or an EU pet passport, and it is not required or accepted by Southwest for pet travel.
Sources
- Pet Policy — Southwest Airlines
- Additional Information About Traveling With Pets — Southwest Airlines
- Destination Requirements for Traveling With Pets — Southwest Airlines
- What type of pet carriers can I bring? — Southwest Airlines
- Optional Travel Charges — Southwest Airlines
- Take a Pet From One U.S. State or Territory to Another (Interstate) — USDA Animal and Plant Health Inspection Service (APHIS)
- Traveling by Air With Service Animals (Final Rule) — U.S. Department of Transportation / Federal Register
- IATA - Traveling with Pets — International Air Transport Association (IATA)
- EU rules on travelling with pets and other animals in the EU — European Commission (Your Europe)
- Pet Travel USDA: APHIS Forms, Fees & Steps — Animal Passport
Animal Passport binds a muzzle biometric to a digital record farmers, buyers, and insurers can verify in the field.