Airfare for Dogs on Southwest: Fees, Carrier Rules, and How to Book

Airfare for dogs on Southwest Airlines is a $125 each-way pet fare (or $35 each way for flights between Hawaiian islands) that lets one small, vaccinated dog ride in an approved carrier under the seat in front of you, according to Southwest's official Optional Travel Charges page. The fare does not cover cargo transport, checked pets, or international flights — Southwest only flies dogs and cats in the cabin, on domestic U.S. routes. Trained service dogs are a separate category entirely and fly free.

This guide breaks down the current Southwest pet fare, carrier requirements, booking limits, and how a "pet fare" differs from the health paperwork and identity documents your dog may still need for the trip.

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

As of September 2026, Southwest Airlines charges $125 each way per pet carrier on mainland U.S. flights, and $35 each way per pet carrier on flights between the Hawaiian Islands, per Southwest's official Optional Travel Charges page. One carrier — which may hold up to two small cats or dogs of the same species if they fit comfortably — counts as your one permitted carry-on or personal item, so you cannot bring a separate bag in addition to the pet carrier.

Southwest has raised this fee over time; it was $95 each way for several years before increasing to the current $125 rate. Because airline fees change, always confirm the live number on Southwest's Optional Travel Charges page before booking.

Southwest's dog and cat travel rules

Southwest's official pet policy, published on its Southwest Support pet policy page, sets the following core requirements:

• Species: Only small, vaccinated domestic cats and dogs are eligible. No other species are accepted.
• Age: Pets must be at least 8 weeks old.
• Location on board: Pets must stay inside the carrier at all times in the gate area, during boarding, during deplaning, and throughout the flight. The carrier must be stowed under the seat in front of you.
• Cabin only: Southwest does not offer cargo or checked-pet transportation of any kind.
• Domestic only: Pets are accepted on domestic U.S. flights only, not on international itineraries.
• One carrier per traveler: Each ticketed passenger may bring one pet carrier, holding up to two same-species pets.
• Behavior: Pets exhibiting disruptive behavior — excessive barking, aggression, or soiling — may be denied boarding, per Southwest's additional pet policy guidance.

Carrier size and weight limits

Southwest requires an airline-approved, leak-proof, ventilated carrier — hard-sided or soft-sided — that fits completely under the seat ahead of you. The maximum approved dimensions are 18.5 inches long x 13.5 inches wide x 8.5 inches high. Measure your dog's carrier against these limits before you get to the airport; gate agents can deny boarding for oversized carriers.

How many pets can fly per flight?

Southwest limits pet carriers to six per flight, allocated on a first-come, first-served basis. Because Southwest does not sell pet reservations the same way it sells seats, you generally need to call 1-800-I-FLY-SWA to confirm and hold a pet spot after booking your own ticket — waiting until departure day is the most common reason pet reservations get turned away.

Southwest pet fare vs. service dog: what's the difference?

A pet fare and a service animal accommodation are not the same thing, and mixing them up can cause a denied boarding. Under the U.S. Department of Transportation's final rule on traveling by air with service animals, effective January 11, 2021, a service animal is legally defined as a dog — regardless of breed — that is individually trained to do work or perform a task for a person with a disability. Under that same 2020 DOT rule, emotional support animals are no longer classed as service animals; airlines are permitted to treat them as pets, subject to the pet fare and carrier rules above.

How to book a dog on a Southwest flight: 4 steps

1. Book your own ticket first. Southwest does not currently let you add a pet during standard online checkout for all fare types, so reserve your seat as normal.
2. Call 1-800-I-FLY-SWA to add the pet. Confirm your flight has an open pet carrier slot — only six are allowed per flight.
3. Confirm your carrier meets the size limit. Verify it is 18.5" x 13.5" x 8.5" or smaller, leak-proof, and ventilated on at least two sides.
4. Pay the Pet Fare at the ticket counter. Southwest's policy states the fare must be paid at the airport ticket counter with an accepted credit card, and it is refundable if you cancel.

Does my dog need a health certificate to fly on Southwest?

Southwest's own pet policy does not require a veterinary health certificate for domestic in-cabin travel. However, some states require an interstate health certificate for dogs crossing state lines regardless of airline policy, and any international connection would require a USDA-endorsed United States Interstate and International Certificate of Health Examination for Small Animals (APHIS Form 7001) from a USDA-accredited veterinarian. Because Southwest does not fly pets internationally at all, APHIS export paperwork does not apply to a Southwest-only itinerary — but it matters the moment your dog's trip continues on another carrier. Animal Passport's own guide on USDA APHIS pet travel requirements walks through that separate export paperwork step by step.

Airfare fare vs. a pet identity document: don't confuse the two

A Southwest pet fare gets your dog a seat. It is not proof of who your dog is, what breed or age it is, or its vaccination and health history — that is a separate identity problem, and it's the one Animal Passport is built for. Animal Passport is a digital identity record for animals that uses a phone-captured muzzle print — a nose print that is unique like a human fingerprint — to bind an owner, breed, estimated age, body condition score, and vaccination history to a single animal record. The age estimate comes from a dental photograph with a confidence score, and the body condition score (1–5) comes from a side-profile photo. It has been used in livestock flood rescue in Pakistan in August 2025, helping farmers reclaim animals after paper ear tags washed away.

That biometric identity record is not an airline pet fare, a government-issued travel document, or a substitute for a USDA APHIS health certificate, a DOT Service Animal Air Transportation Form, or any airline's pet policy. If your keyword search brought you here because you're comparing "pet passport" products, treat the EU PETS scheme, USDA APHIS export certificates, and DOT service animal rules as the official travel-document authorities, and treat Animal Passport as a separate identity and record-keeping tool for the animal itself. You can read more about how the identity record works on the Animal Passport homepage and the Animal Passport blog.

Frequently asked questions

How much is Southwest's pet fare in 2026?

Southwest charges $125 each way per pet carrier on mainland U.S. flights and $35 each way per pet carrier on flights between the Hawaiian Islands, according to Southwest's official Optional Travel Charges page. Confirm the current fee on Southwest's site before booking, since airline fees change.

Can I check my dog as cargo on Southwest?

No. Southwest does not offer cargo or checked-pet transportation of any kind — all pets travel in the cabin, in an approved carrier, under the seat in front of you.

Does Southwest fly pets internationally?

No. Southwest's pet policy covers domestic U.S. flights only; pets are not accepted on international itineraries.

How many dogs can fly on one Southwest flight?

Southwest limits pet carriers to six per flight on a first-come, first-served basis, and each carrier may hold up to two small dogs of the same species if they fit comfortably together.

Do service dogs pay the pet fare on Southwest?

No. Trained service dogs are not classified as pets under the U.S. Department of Transportation's December 2020 final rule and fly free, but the handler must submit a DOT Service Animal Air Transportation Form to the airline.

What size carrier does Southwest allow for a dog?

Southwest's maximum approved pet carrier size is 18.5 inches long by 13.5 inches wide by 8.5 inches high, and it must fit fully under the seat in front of you.

Is Animal Passport a pet travel document I can use to fly my dog?

No. Animal Passport is a biometric identity record — built around a phone-captured muzzle print, estimated age, body condition score, and vaccination history — not an airline booking product, a government travel document, or a substitute for Southwest's pet fare, a USDA APHIS health certificate, or a DOT service animal form.

Is the Southwest pet fare refundable?

Southwest's pet policy states the Pet Fare is refundable if you cancel your reservation, unlike some non-refundable fare add-ons on other airlines.