Here's what I wish someone had told me before booking Southwest for a dog: they welcome small dogs in the cabin, but cargo is off the table entirely. That single line changes everything about how you plan. Cooper has done this trip three times now, and knowing a carrier's limits up front is what saves you the last-minute scramble. Let's walk through it together.

Southwest Airlines's pet policy splits into cabin and cargo. This page summarizes the weight limits, fees, brachycephalic-breed restrictions, and carrier specifications for both modes — sourced from the airline's official pet pages.

How Southwest Airlines handles your pet

Each fact comes straight from the operator’s published policy. Tap the to read the exact wording; the opens the source page.

In the cabin Accepted
In the hold / cargo Not accepted

Cabin policy

Pets accepted Acceptedverified 2026-08-28
Banned destinations Yesverified 2026-08-08
Min age weeks8 weeksverified 2026-07-15
Max pets per carrier2verified 2026-07-15
Crate must have/behard-sided ok, ventilated, a carrierverified 2026-07-22

Hold & cargo policy

Hold: Advance booking required Yesverified 2026-08-28
Hold: Crate must have/beventilated, a carrierverified 2026-08-15
Cargo: Pets accepted Not acceptedverified 2026-07-15

Service & assistance animals

Recognized Yesverified 2026-08-13
Breed restrictionsService Animal means a dog, regardless of breedverified 2026-08-28
Southwest charges a Carryon Pet Charge of 125 USD per pet carrier on U.S. Mainland flights, one way. Budget 125 USD for each direction of travel. A round trip means 250 USD total in pet charges. Add this amount when comparing fares. Pay it at the time of booking or check-in as the carrier requires for the in-cabin carrier slot.
You've got the big Southwest decisions in front of you now, and that's honestly half the battle. Every trip has its own wrinkles, though, so before you book anything, build a personalized plan for your exact route and your own dog. Pawgo's plan-builder walks you through it step by step, the way I wish someone had done for me. You've got this.
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Glossary

ISO chip
ISO 11784/11785 — the universal microchip standard.
FAVN
Fluorescent Antibody Virus Neutralization — a rabies serology test required by rabies-free destinations.
Brachycephalic
Snub-nosed breeds (French Bulldogs, Pugs, Persians, Himalayans) with restricted airline acceptance due to heat-stress risk.
AVIH
Animal Vehicle In Hold — IATA's term for cargo pet shipment, with fees that vary by carrier and route.