Southwest Airlines Pet Policy 2026: Fees, Carrier Size and Where Pets Can’t Fly

Southwest Pet Policy at a Glance

Source: Southwest's official pet policy, Southwest optional travel charges, checked October 11, 2026.

What Most Sites Get Wrong

Southwest's pet rules are short, but they're spread across six help pages, and most guides copy an older version. These are the errors that matter at the gate.

• "The carrier can be 18.5 x 8.5 x 13.5 inches."That's an old figure. Southwest's current maximum is 18 inches long, 10.5 inches wide and 10 inches high. The 10-inch height is the number that rules out carriers bought for other airlines, which usually allow 11.
• "Pick a window or aisle seat for more room."Southwest says under-seat space is more limited in some seats, including aisle seats. You can't sit in an exit row or the first row with a pet. Southwest now assigns seats, so choose yours with that in mind.
• "Only six pets per flight."Southwest's current pet pages say space is limited but don't give a number. Call early either way.
• "No pets to mainland Hawaii, but interisland is fine."There's no "mainland Hawaii." The rule is no pets on any flight to or from Hawaii, and pets are fine on flights between the Hawaiian Islands, for $35.
• "Too big for Southwest? Use Delta Cargo."Delta Cargo has a global embargo on household pets. Of the major U.S. airlines, only American still ships pets as cargo, through American PetEmbark.
• "A child flying alone can bring the family cat."Unaccompanied minors can't travel with a pet on Southwest.

Source: Southwest's official pet policy, Southwest pet carrier rules, Southwest onboard rules, checked October 11, 2026.

Fees and How You Pay

• Per carrier, not per pet. Two cats in one carrier pay one $125 fare.
• Pay at the ticket counter at the airport, with an accepted credit card.
• Refundable. If you cancel your reservation, the pet fare is refunded.
• No points. Pets don't earn Rapid Rewards points.
• Pet strollers pay standard checked bag fees.

Source: Southwest's official pet policy, Southwest optional travel charges, checked October 11, 2026.

Carrier Size and What Else You Can Bring

The carrier must be designed as a pet carrier, leak-proof and well ventilated. Your cat or dog, head and tail included, has to be fully inside and able to stand up and move around easily. Southwest recommends a soft-sided carrier, because under-seat space varies with seat type and position on the plane.

One carrier per ticketed customer. It can hold up to two small cats or two small dogs, never one of each.

Source: Southwest's official pet policy, Southwest pet carrier rules, checked October 11, 2026.

Seats and Onboard Rules

• No pets in an exit row or the first row (bulkhead).
• A pet can never occupy a passenger seat.
• The carrier stays under the seat in front of you for the whole flight.
• The pet stays fully inside the carrier, head and tail included, in the gate area, during boarding and deplaning, and for the entire flight.
• Aisle seats can have less under-seat room.
• Board with your assigned boarding group.

A pet that scratches, whines or barks excessively, growls, bites, jumps, lunges, or urinates or defecates in the cabin or gate area can be denied boarding.

Source: Southwest's official pet policy, Southwest onboard rules, checked October 11, 2026.

Where Southwest Won't Fly Your Pet

"Any itinerary that includes an international flight" means a domestic leg is off limits too if it connects to Mexico, the Caribbean or Central America on the same booking. On a Getaways by Southwest vacation package, also check your hotel's and rental car company's pet policies.

Source: Southwest's official pet policy, Southwest pet destination rules, checked October 11, 2026.

How to Book Your Pet on Southwest

1. 1
   Check the route. Domestic only, nothing to or from Hawaii, no international leg anywhere on the booking. The traveler can't be an unaccompanied minor.
2. 2
   Book your ticket and seat. Avoid exit rows and the first row. Southwest notes that aisle seats can have less room under the seat.
3. 3
   Call Southwest to add the pet. Space is limited, and Southwest recommends reserving the pet in advance by phone at 1-800-I-FLY-SWA (1-800-435-9792). [VERIFY: whether pets can now be added online or in the Southwest app]
4. 4
   Measure the carrier. 18 x 10.5 x 10 inches at most, or Southwest's own 15 x 10 x 10 inch carrier.
5. 5
   Pay at the ticket counter on travel day with an accepted credit card: $125, or $35 between the Hawaiian Islands.

Source: Southwest's official pet policy, checked October 11, 2026.

At the Airport

• Ticket counter: pay the pet fare there.
• Security: you hold your pet and walk through the scanner while the carrier is X-rayed. All carriers can be searched.
• Gate area: the pet stays fully inside the carrier.
• Relief areas: available at every Southwest airport, but Southwest won't hold a flight while you use one.

Source: Southwest's official pet policy, Southwest airport rules for pets, checked October 11, 2026.

Is Your Pet Fit to Fly?

Southwest has no breed ban, but it warns that animals with heart disease, anxiety disorders or brachycephalic airways, as in pugs, bulldogs and Persian cats, are more likely to have problems in flight. It leaves the decision to you and your vet. Your pet must be at least 8 weeks old and vaccinated.

Source: Southwest's official pet policy, Southwest additional pet information, checked October 11, 2026.

Service Dogs and Emotional Support Animals

Trained service dogs fly free in the cabin and aren't counted as pets. Under U.S. Department of Transportation rules, airlines can require the DOT service animal form, plus a relief attestation for flights of 8 hours or more. Emotional support animals aren't service animals under those rules, so on Southwest they fly as pets: $125 each way, carrier rules and all.

Southwest vs Delta vs United vs American

Southwest is the cheapest of the four for a domestic trip and the best deal for two small pets, which share one carrier and one $125 fare. Its lower carrier height is the trade-off: a carrier that fits Delta's or United's limits may be too tall for Southwest.

Sources: Southwest's official pet policy, Delta's official pet policy, United's official pet policy, American's official pet policy, checked October 11, 2026.

Southwest Pet Policy FAQ

Southwest Pet Travel Checklist

• Small, vaccinated cat or dog, at least 8 weeks old
• Domestic itinerary, no international leg, nothing to or from Hawaii
• Not traveling as an unaccompanied minor
• Carrier no larger than 18 x 10.5 x 10 in, leak-proof, ventilated, designed for pets
• Two pets only if same species and both fit in one carrier
• Seat is not an exit row or the first row
• Pet reserved by calling Southwest in advance
• One extra bag only: personal item or carry-on
• $125 each way ($35 interisland Hawaii) on an accepted credit card at the ticket counter
• Vet consulted if your pet is brachycephalic, anxious or has heart disease

Every rule on this page was checked against Southwest's official pet policy and its linked help pages on October 11, 2026. Airlines change pet rules without notice, so check the official page again in the week you fly.