Southwest Airlines
Travel With Dogs

How Strict is Southwest About Pet Carrier Size? Fact Check Before you Fly


There are so many things to remember when traveling, especially with a pet! Will purchasing a new carrier have to be added to your list? How strict is Southwest about pet carrier size?

Southwest seems to allow pet carriers that are slightly too large so long as they fit under the seat. However, we recommend purchasing a carrier of the correct size rather than taking the risk. If your cat or dog is more comfortable in a carrier just an inch or two too big, try bringing the bigger carrier along with a backup just in case.

Dog Is More Comfortable in a Carrier
Your dog is more comfortable in a carrier

You never know if you’ll be the one held accountable by an employee having a bad day, or who is enforcing the rules more strictly.

In this article, we’ll take a look at Southwest’s pet policy as well as some cases where people were allowed on the plane with carriers that were slightly too large.

What is Southwest’s Pet Policy?

Southwest’s pet policy for in-cabin carriers are as follows:

  • No bigger than 18.5” long x 8.5” high x 13.5” wide
  • Soft-sided and hard-sided carriers allowed
  • Has to be designed as a pet carrier, no other containers allowed
  • One carrier allowed per customer
  • Up to two cats or dogs of the same species in one carrier
  • Pet(s) must be able to stand and turn within the carrier
  • Pet(s) must be kept in the carrier through the entire flight
  • Carriers replace either your carry on or personal item
  • Pets cannot travel with minors
  • Pets cannot travel internationally
  • Pets must be at least 8 weeks old to fly

In addition, Southwest only allows up to 6 pets on a single flight. They book pets on a first-come, first-serve basis, therefore you should reserve a place for your pet when you book your own tickets.

Book Your Own Pets Tickets
Don’t forget to book your pets tickets too

Otherwise, the flight may be full and not allow you and your pet to travel. Southwest only allows pets to travel in-cabin with you.

How Strict is Southwest about Pet Carrier Size?

Southwest’s own carrier that they sell seems to not follow their size limits, which confuses consumers. Does Southwest only allow this size carrier if you purchase a carrier directly from them?

We’re not quite sure why Southwest’s carrier goes beyond their stated dimensions, however, this does confirm that there is at least one inch of wiggle room when it comes to space beneath your seat.

Dog in the Large Carrier for Travel
Make sure your dog is in an approved carrier

A slightly too-large pet carrier will fit, but will it be allowed on the plane?

Anecdotally, yes—but we advise being cautious and bringing a backup carrier to ensure you get to board your flight. Either that or come prepared to purchase the carrier Southwest sells.

We found two instances where people were able to board just fine with carriers outside of the limitations—this one with a carrier two inches too tall, and someone else who didn’t specify the dimensions of their carrier.

Best Cat Carrier for Traveling
Test the carrier out at home

Again, these are anecdotal and don’t confirm that you will be allowed on the plane with a carrier that goes beyond Southwest’s limitations.

We advise doing as these people have, and bringing a backup carrier that fits the requirements just in case.

Things might not go as smoothly for you, and you might get an airline employee who’s stricter about the rules!