Southwest Airlines Pet Fee: What It Costs and How to Book in 2026

The Southwest Airlines pet fee — officially called the Pet Fare — is $125 each way per pet carrier for small, vaccinated cats and dogs traveling in the cabin on U.S. mainland flights, according to Southwest Airlines' official Optional Travel Charges page. The fee drops to $35 each way for travel between the Hawaiian Islands, but pets cannot fly to, from, or over Hawaii, and Southwest does not accept pets on any international itinerary. Only in-cabin travel is offered; there is no cargo option.

How Much Does Southwest Charge to Fly With a Pet?

Southwest Airlines lists its pet charge as a Pet Fare of $125 per pet carrier, each way, on its official Optional Travel Charges page (southwest.com, checked August 2026). This is a flat per-carrier charge, not a per-animal charge, and one carrier may legally hold up to two pets of the same species. The fee is charged separately from your ticket and is not covered by Rapid Rewards points.

Southwest's pet fee has risen over time. Industry and travel-press reporting places the fee at $75 in the mid-2000s and $95 in more recent years before the current $125 rate took effect. Southwest's own site does not publish a change-log with exact increase dates, so travelers should treat $125 as the current, authoritative figure and confirm at booking, since airline ancillary fees change without much notice.

Southwest Pet Fee at a Glance

Who and What Can Fly Under Southwest's Pet Program

Southwest's official pet policy, published at support.southwest.com, restricts the in-cabin pet program to small, vaccinated domestic cats and dogs at least 8 weeks old. No other species are eligible. Pets must stay inside an approved carrier for the entire time they are in the gate area, during boarding and deplaning, and throughout the flight — they may never occupy a seat, and carriers cannot be placed in exit rows or the bulkhead (first) row.

Third-party pet-travel guides, including BringFido and Upgraded Points, consistently report Southwest's under-seat carrier limit at roughly 18.5 inches long by 13.5 inches wide, with published height figures varying between 8.5 and 9.5 inches depending on the source — Southwest's own help-center pages describe the requirement functionally ("must fit under the seat in front of you") rather than publishing a single fixed dimension. Because under-seat space varies by aircraft and seat location, Southwest recommends a soft-sided, collapsible carrier and advises confirming fit with the gate agent.

How to Book a Pet on Southwest

1. Call ahead. Southwest limits the number of pet carriers per flight and books them first-come, first-served, so reserve a spot by calling 1-800-I-FLY-SWA before or when you book your own ticket.
2. Confirm eligibility. Have your pet's age, species, and vaccination status ready — Southwest only accepts cats and dogs at least 8 weeks old.
3. Check your carrier. It must be leak-proof, ventilated, and small enough to stow flat under the seat in front of you; soft-sided carriers fit best.
4. Pay the Pet Fare at the airport. Southwest requires the fee to be paid at the ticket counter with a credit card on the day of travel, not during online checkout.
5. Check destination rules. Puerto Rico travel involves additional USDA documentation, and Hawaii and international routes are off-limits to pets entirely, per Southwest's destination-requirements page.
6. Arrive early. At the security checkpoint you'll carry your pet through the screening device by hand while the carrier is X-rayed separately.

Southwest Pet Fee vs. Service Animals

Southwest's paid pet program is legally and operationally separate from its service animal policy. Effective March 1, 2021, Southwest Airlines began accepting only trained service dogs at no charge, following the U.S. Department of Transportation's December 2020 final rule amending the Air Carrier Access Act, which redefined a service animal as "a dog, regardless of breed or type, that is individually trained to do work or perform tasks for the benefit of a qualified individual with a disability" (Federal Register, effective January 11, 2021). Under that same rule, airlines nationwide stopped being required to transport emotional support animals for free. Travelers whose animals do not meet the DOT's trained-service-dog definition must use Southwest's standard paid Pet Fare program instead, subject to the cat/dog, 8-week-minimum, and in-cabin-only rules above.

Is a Pet Fee the Same as a Pet Passport?

No. A domestic Southwest flight requires only proof of vaccination and payment of the $125 Pet Fare — it does not require a "pet passport" of any kind. The term pet passport usually refers to the European Union's PETS travel document scheme, which is a legal requirement for moving dogs, cats, and ferrets between EU countries and is unrelated to U.S. domestic airline fees. Travelers flying Southwest within the U.S. mainland do not need an EU pet passport, a USDA international health certificate, or any equivalent document; those requirements only apply to international pet travel, which Southwest does not offer.

This is also a good place to flag a separate but related category: digital identity tools for animals. Animal Passport is a phone-based, muzzle-biometric livestock identification product — it uses a nose-print scan the way a fingerprint identifies a person, binding an owner's record to a specific animal along with breed, an estimated age from a dental photo, and a body condition score from a side-profile image. 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. It is a livestock-identity and recovery tool, not an airline travel document, and it does not replace a Southwest Pet Fare, a USDA health certificate, or an EU pet passport for air travel. For more on how digital animal ID differs from legal travel documents, see the Animal Passport blog.

Southwest vs. Other Airlines' Pet Fees

Southwest's $125 in-cabin Pet Fare sits close to what other major U.S. carriers now charge, though airlines have been raising pet fees industry-wide and figures should always be confirmed directly before booking. Delta Air Lines, for example, raised its own domestic in-cabin pet fee from $95 to $150 each way for tickets issued on or after April 8, 2025, according to Delta's official pet travel page — a roughly 58% increase in a single change. JetBlue Airways charges $125 each way for in-cabin pets under 20 pounds, per pet-travel resource BringFido, similar to Southwest's rate, though JetBlue's own help page does not publish the dollar figure directly.

Pet Fee Comparison Table

What differentiates Southwest from Delta and JetBlue is booking mechanics rather than price: Southwest requires a phone reservation for every pet rather than an online add-on, and it caps the number of pet carriers allowed per flight. That means pet space can sell out even when passenger seats remain available, so calling well before your travel date matters more on Southwest than on carriers that let you add a pet during online checkout.

Health and Safety Considerations

Southwest's own help-center materials flag that some animals face higher in-flight risk than others: "Animals with heart disease, anxiety disorders, or brachycephalic airways are more susceptible to complications during flight," the airline states in its additional pet-policy guidance. Brachycephalic (flat-faced) breeds — such as pugs, bulldogs, and Persian cats — are widely recognized in veterinary literature as having reduced respiratory tolerance for stress and altitude changes, so owners of these breeds should talk to a veterinarian before booking cabin travel. Southwest's rules exist independently of any vaccination or identification record you may keep for your pet at home; the airline only asks for proof of current vaccination at check-in, not a formal travel passport.

Common Mistakes That Cost Travelers Money

• Assuming you can add a pet online. Southwest requires a phone reservation for pets; showing up without one risks being turned away if the flight's pet quota is full.
• Buying a carrier that's too tall. Height is the dimension most likely to fail the under-seat test — measure your specific carrier, not just the advertised size class.
• Forgetting Hawaii and international restrictions. No pet fee gets a cat or dog onto a Hawaii or international Southwest itinerary; the airline does not carry pets on those routes at all.
• Confusing an emotional support animal with a service dog. Since March 1, 2021, only trained service dogs fly free under DOT rules; emotional support animals must go through the standard paid pet program if they meet the cat/dog eligibility rules.

Bottom Line

As of August 2026, the Southwest Airlines pet fee is $125 each way per carrier for in-cabin cats and dogs on U.S. mainland routes, $35 each way between Hawaiian Islands, and unavailable on Hawaii-mainland or international itineraries. Book by phone in advance, confirm your carrier fits under the seat, and pay the fare at the airport counter on travel day.