Southwest Rules for Dogs: Fees, Carrier Limits, and Booking Steps

Southwest rules for dogs are the airline's in-cabin pet policy: small, vaccinated domestic dogs may fly inside an approved carrier under the seat on eligible U.S. domestic flights for a Pet Fare of $125 per carrier each way on the U.S. mainland or $35 between Hawaiian Islands, according to Southwest Airlines' Optional Travel Charges page. Southwest does not transport dogs as checked baggage or cargo, does not accept pets on international itineraries, and limits each flight to six pet carriers booked by phone. As of August 2026, emotional support dogs follow the paid pet rules; only individually trained service dogs travel free with U.S. Department of Transportation (DOT) paperwork.

This guide summarizes Southwest Airlines' published pet, service-dog, and destination rules from primary sources. It also explains how federal animal-travel guidance from the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) may affect your paperwork—and how that differs from Animal Passport, a phone-based biometric livestock identification record, not a government-issued airline or EU pet passport.

Last updated: August 19, 2026. Airline fees and carrier dimensions change; confirm current rules on Southwest.com before booking.

Quick Answer: Can My Dog Fly Southwest?

Southwest Airlines accepts small, vaccinated domestic dogs at least eight weeks old in the aircraft cabin when they remain inside an airline-approved carrier that fits under the seat. Dogs cannot fly in cargo, cannot travel on international routes, and generally cannot fly to or from Hawaii on mainland routes—only between Hawaiian Islands. Booking requires a phone call; the Pet Fare is collected at the airport ticket counter.

Southwest Pet Policy for Dogs at a Glance

Step-by-Step: Flying Your Dog on Southwest

1. Confirm route eligibility. Southwest allows in-cabin pets on domestic flights within the United States, but pets are not allowed on international flights or any itinerary that includes an international segment, according to Southwest's destination pet information page. Pets are also not allowed on flights to or from Hawaii, though they are accepted on flights between Hawaiian Islands.
2. Book your own ticket. Purchase your passenger ticket through Southwest.com or by phone as you normally would.
3. Call immediately to add your dog. Southwest's Contract of Carriage states pet reservations can only be booked by calling Southwest. Because each flight accepts no more than six pet carriers on a first-come, first-served basis, early phone booking is critical.
4. Choose an approved carrier. Your dog—including head and tail—must remain fully inside a leak-proof, ventilated carrier designed for pets. The carrier must fit under the seat in front of you for the entire flight.
5. Check in and pay the Pet Fare at the ticket counter. Southwest requires you to check in your pet and pay the Pet Fare at the airport ticket counter with an accepted credit card before proceeding to the departure gate.
6. Prepare destination paperwork if required. Southwest requires pets to be vaccinated and notes that Puerto Rico and some other destinations may impose additional entry requirements. USDA APHIS advises contacting the airline about health certificates because airline documentation rules can differ from state or territory import rules.

Carrier Size and Type Rules

Southwest's current approved pet carrier page lists these maximum dimensions:

• Southwest-branded pet carrier: 15 inches long × 10 inches wide × 10 inches high (available at ticket counters for $58 per carrier, per Southwest Optional Travel Charges).
• Other approved pet carriers: 18 inches long × 10.5 inches wide × 10 inches high maximum.

Carriers may be soft-sided or hard-sided but must be specifically designed as pet carriers, leak-proof, and well ventilated. Your dog must be able to stand up and move around inside with ease. Southwest recommends a soft-sided carrier because under-seat space varies by aircraft and seat type; aisle seats may offer less room.

Your pet carrier counts as either your personal item or your carry-on bag—you may board with a pet carrier plus one personal item, or a pet carrier plus one standard carry-on, but not both a full carry-on and a separate personal item in addition to the carrier.

Can Large Dogs Fly on Southwest?

No. Because Southwest accepts pets in the cabin only and does not operate a checked-pet or cargo program, any dog too large to fit comfortably in an under-seat carrier cannot travel on Southwest. Medium and large breeds generally require an airline that offers cargo transport or ground shipping.

Onboard and Airport Behavior Rules

Southwest's onboard pet expectations require that dogs:

• Remain secured inside the carrier—including head and tail—at all times in the gate area, during boarding and deplaning, and for the entire flight.
• Never occupy a passenger seat.
• Not sit in an exit row or the first-row bulkhead.
• Stay under the handler's control and avoid disruptive behavior such as excessive barking, growling, biting, jumping, lunging, or urinating/defecating in the cabin or gate area.

Southwest retains the right to refuse any pet that shows aggressive behavior or other characteristics incompatible with air travel, according to its Contract of Carriage. Unaccompanied minors may not travel with a pet.

Destination-Specific Southwest Rules for Dogs

Hawaii

Southwest does not allow pets on flights to or from Hawaii. Pets are accepted only on interisland flights within Hawaii at the lower $35 Pet Fare. If you need to move a dog between the U.S. mainland and Hawaii, you must use another carrier or transport method and comply with the Hawaii Department of Agriculture (HDOA) rabies quarantine and import program.

Hawaii's Five-Day-or-Less quarantine program requires pre-arrival steps that can take months, including microchip identification, two rabies vaccinations spaced at least 90 days apart, a passing OIE-FAVN rabies blood test, a 120-day waiting period after the lab receives the blood sample, and paperwork submitted more than 10 days before arrival, according to HDOA published program requirements. Even when another airline accepts your dog in cabin or cargo, Hawaii import law—not the airline—governs entry.

Puerto Rico and Other U.S. Territories

Southwest accepts pets on domestic routes to Puerto Rico but states that specific requirements may apply. Puerto Rico and individual states may require health certificates or proof of rabies vaccination beyond Southwest's baseline vaccination expectation. Check both the airline and the destination animal health authority before travel.

International Travel

Southwest's Contract of Carriage and destination information page state that no pets are accepted on international itineraries. If you need to fly a dog internationally, you must use a different airline and follow the destination country's import rules, which USDA APHIS publishes on its pet-travel pages. EU pet passports and the EU Pet Travel Scheme (PETS) are official veterinary documents for movement within Europe; they are separate from Animal Passport's biometric livestock ID product.

Service Dogs vs. Pets vs. Emotional Support Animals

Southwest rules for dogs split into three distinct categories:

Trained Service Dogs (No Pet Fare)

Southwest accepts only fully trained service dogs—dogs individually trained to perform tasks for a person with a disability. Service dogs must be harnessed, leashed, or tethered, behave under the handler's control, and travel with a completed U.S. Department of Transportation Service Animal Air Transportation Form dated on or after the ticket purchase date, presented at the ticket counter or gate. Southwest does not accept vests, ID cards, or registration certificates in place of the DOT form.

Under the Air Carrier Access Act (ACAA), as summarized by the U.S. Department of Transportation in 2020 final-rule guidance still reflected on DOT's service animal page, airlines may require the DOT health-and-behavior attestation form and, on flights of eight hours or more, a separate relief attestation form. Service dogs may sit at your feet or in your lap if no larger than a child under two. Additional documentation may be required for Hawaii, Puerto Rico, or international segments.

Emotional Support Animals (Paid Pet Rules)

Effective March 1, 2021, Southwest no longer transports emotional support animals as service animals, consistent with DOT's 2020 service-animal final rule, according to a Southwest Airlines press release. ESAs may travel only under the standard in-cabin pet policy, including carrier confinement and the Pet Fare.

Regular Pets (Paid Pet Rules)

All non-service dogs travel as pets: in an under-seat carrier, with the Pet Fare paid at check-in, and subject to the six-carrier-per-flight cap.

Federal Health and Age Requirements That Apply to Air Travel

Even when Southwest does not ask for a health certificate on a mainland domestic route, federal animal-movement guidance still matters:

• Minimum age: USDA regulations require dogs and cats to be at least eight weeks old and fully weaned before traveling by air, according to USDA APHIS guidance on preparing pets for air travel—a threshold Southwest mirrors in its pet policy.
• Health certificate timing: USDA APHIS states that a Health and Acclimation certificate should be signed by a licensed veterinarian within 10 days of travel and should document the acceptable temperature range for transport. Airlines may impose their own documentation requirements; APHIS advises contacting the carrier directly.
• Airline-specific forms: If an airline does not require a specific health form, APHIS notes that APHIS Form 7001 may be used for boarding, though APHIS endorses only country-specific export certificates for international entry.

Always verify both airline and destination-state or territory rules. Requirements for Puerto Rico, Hawaii interisland travel with a service dog, or any cross-border itinerary can exceed Southwest's published pet policy.

Southwest Rules for Dogs vs. Other Major U.S. Airlines

How Animal Passport Relates to Southwest Travel (and What It Does Not Do)

Travelers searching "southwest rules for dogs" are usually planning a cabin flight, not registering livestock. Still, keeping accurate health and identity records makes airline and destination checks smoother.

Animal Passport is a digital animal and livestock identification record that uses muzzle biometrics—each nose print is unique, similar to a fingerprint—captured on a phone. A record can bind owner information, breed, estimated age (from a dental photograph with a confidence score), body condition score (1–5 from a side-profile photo), and vaccination history. In August 2025, similar biometric records were used in livestock flood rescue in Pakistan so farmers could reclaim animals when paper ear tags washed away.

Important distinctions:

• Animal Passport is not a government-issued pet passport, EU pet passport, or airline boarding pass.
• It does not replace a USDA-accredited veterinarian health certificate, DOT service-animal form, Hawaii HDOA import packet, or any document an airline or territory legally requires.
• Southwest's rules for dogs are set solely by Southwest and applicable federal, state, and territory law—not by private ID apps.

For field-record context and livestock identification beyond airline policy, see the Animal Passport blog.

Practical Tips From Southwest's Own Guidance

• Book early by phone because only six pet carriers are allowed per scheduled flight, according to Southwest's Contract of Carriage and Newsroom guidance.
• Practice carrier confinement before travel; disruptive behavior is grounds for denial.
• Prefer soft-sided carriers to accommodate varying under-seat dimensions, especially away from aisle seats.
• Line the carrier with absorbent material and carry cleanup supplies; you must remove your dog at TSA screening while the empty carrier is X-rayed, per Southwest's traveler tips.
• Reconfirm fees on Southwest's Optional Travel Charges page before departure; Pet Fare pricing is subject to change.

Key Takeaways for Dog Owners

Southwest's dog rules are straightforward but strict: cabin-only, small dogs in carriers, phone reservations, and no international or mainland-Hawaii pet routes. Service dogs are the exception and fly under DOT paperwork without a Pet Fare. Emotional support dogs are treated as pets. Layer federal USDA age and health guidance plus destination import law on top of airline policy before you fly.