Flying with a dog or cat on Southwest
Southwest publishes 18.5 × 13.5 × 8.5 in for a soft-sided carrier under the seat. That is the number that decides whether you get on the plane. Everything below was read on the Southwest policy page, and the link to it is at the bottom.
Soft-sided maximum
18.5 × 13.5 × 8.5 in — length × width × height.
Hard-sided maximum
Same as soft-sided
What it costs
$125 each way, per carrier
Weight limit
Not published
Pets per passenger
One carrier per passenger. A carrier may hold two small cats or dogs of the same species.
Pets per flight
Space is limited and not guaranteed. Southwest recommends booking by phone.
The one to watch on this airline
The 8.5-inch ceiling is the joint lowest on this list. Southwest is wide and flat, not tall — a carrier that clears American may not clear this.
Which of our carriers fits under the seat on Southwest
Measured against 18.5 × 13.5 × 8.5 in. Length and width have to clear as published. Height gets one inch of give, because a soft side compresses — and no more than one.
Right now, nothing we sell clears this one. Southwest publishes 18.5 × 13.5 × 8.5 in, and nothing in our catalogue clears all three of those numbers. We could list you something close and let you find out at the gate. We would rather tell you here.
We are actively looking for a carrier that fits. If you want an email the day we find one, the checklist sign-up at the bottom of this page is the fastest way to hear about it — or write to us with your pet's measurements and we will tell you honestly whether anything on the market works for this route.
Before you book
How to book the pet
Southwest recommends calling to reserve, because space is limited.
Minimum age
8 weeks.
Your other bags
The carrier counts toward your carry-on allowance.
The widest footprint of the majors, but the shallowest ceiling on this list at 8.5 inches. Wide and flat, not tall.
Policies change without notice, and the airline's own page is the authority — not this one. Read the Southwest pet policy, or go back to the full guide covering all nine airlines.