What Southwest Allows in 2026
Southwest is simple compared with most airlines. Small vaccinated domestic dogs and cats can ride in the cabin if they fit in an approved carrier under the seat. No cargo. No checked pets. No "my dog is calm so he can sit on my lap" exception.
The pet must stay in the carrier in the gate area, during boarding, during deplaning, and for the whole flight. That is the part people ignore. It is also the part agents enforce when a pet is barking, scratching, lunging, or out of the bag.
Southwest says pets must be at least 8 weeks old. Unaccompanied minors cannot travel with a pet. A pet carrier counts as either the carry-on or the personal item, so plan the bag setup before airport day.
Fees, Carrier Rules, and Cabin Limits
| Rule | Southwest policy |
|---|---|
| Pet fee | $125 each way on U.S. mainland routes; $35 each way between Hawaiian Islands |
| Pets allowed | Small vaccinated domestic cats and dogs |
| Per passenger | One carrier per ticketed customer |
| Per carrier | Up to two small cats or dogs of the same species if they fit safely |
| Booking | Reserve space in advance by calling Southwest |
The published Southwest pet carrier for purchase is listed at $58, but you do not have to buy that exact one if your carrier meets the rules and fits under the seat. Soft-sided carriers are usually easier for airline travel because they compress a little and give the pet more usable shape.
Plain talk: the carrier fitting under the seat matters more than the breed name. A tiny poodle that cannot stay zipped in the carrier is a no. A quiet cat that fits cleanly is usually the easier passenger.
Routes That Do Not Work for Pets
Southwest does not accept pets on international itineraries. It also does not accept pets on flights to or from Hawaii. That knocks out a lot of moves where people assume "domestic airline" means "domestic pet move."
Puerto Rico is different. Southwest points travelers to destination-specific requirements for Puerto Rico, so do not book that trip based only on the cabin pet rule. Check the health paperwork before taking a deposit or paying a flight nanny.
Do not wing Hawaii. Hawaii has strict animal import rules, and Southwest's regular pet policy does not cover flights to or from Hawaii. Use a carrier with a Hawaii-ready pet program instead.
Flight Nanny Notes for Southwest
Southwest can work well for flight nannies on simple domestic routes. The booking process is old-school: reserve the passenger ticket, then call to add the pet because pet space is limited.
For owners, ask the nanny for proof that the pet is added to the reservation, not just a screenshot of a flight search. Anyone can send a flight number. A confirmed flight nanny should be able to show a ticketed reservation and the pet booking details with private numbers partly hidden.
For nannies, price the job like a real job. Ticket, pet fare, parking, carrier time, airport wait time, delay risk. If you quote it like a favor, you will resent it by boarding group B.
Official Sources to Check Before Booking
Policies change. Before you pay, check Southwest's pet policy, its optional travel charges, and the airport expectations page for pet behavior and check-in rules.