Southwest Airlines in-cabin pet policy — and the carriers that fit
Southwest Airlines allows small pets in the cabin in a carrier up to 18 × 10.5 × 10 in, stowed under the seat in front of you. Already own a carrier? Enter its measurements below to check it against this limit. The in-cabin fee is $125 each way (US mainland). 2 of the 15 carriers we track clear that published limit.
The Sherpa Original Deluxe (Small) leaves the most room — 0.5" on its tightest dimension, while the Petmate Soft-Sided Kennel Cab (Medium) only just squeaks in with nothing to spare. Southwest's 10" height ceiling sits mid-pack among the 77 airlines we track (shared with Air Transat, Avianca, Contour): Air Europa, Allegiant, American and American Eagle (regional, incl. Republic Airways) allow more, while EL AL Israel allows only 7".
Will your carrier fit Southwest Airlines?
Measure the outside of your carrier (bulges included) and enter it below. The check uses Southwest Airlines’s published 18 × 10.5 × 10 in limit — height is checked strictly, the footprint may rotate.
Carriers that clear Southwest Airlines (18 × 10.5 × 10 in)
Roomiest margin first. Sized to the airline’s limit, not to your pet — measure your pet first →
| Carrier | Size | Fit | Buy |
|---|---|---|---|
Sherpa Original Deluxe (Small) up to ~8 lb · max pet 13″ long × 7.5″ tall | 15 × 10 × 8.5 in | Fits 0.5" spare | See on Amazon → |
 Petmate Soft-Sided Kennel Cab (Medium) up to ~10 lb | 17 × 10 × 10 in | Exact fit 0" spare | See on Amazon → |
Affiliate link — we may earn a small commission at no extra cost to you. It never changes our specs or which carriers we list.
Southwest Airlines pet rules
| Max carrier size (published) | 18 × 10.5 × 10 in |
| Carrier size caveat | Southwest lists its own branded carrier separately at 15 × 10 × 10 in; every other carrier must be within 18 × 10.5 × 10 in. It recommends a soft-sided carrier because under-seat space varies by seat type and location, and is tighter in some seats, including aisle seats. |
| Soft-sided required? | Soft recommended; hard allowed within its limit |
| In-cabin fee | $125 each way (US mainland); $35 between the Hawaiian Islands · compare all airlines → |
| Species allowed | cats, dogs |
| Minimum age | At least 8 weeks |
| Pets | 1 carrier per passenger; 2 same-species pets may share one compliant carrier |
| Booking | Space is limited — Southwest recommends reserving in advance by calling; the Pet Fare is paid at the Southwest ticket counter and is refunded if you cancel · what to book, buy and pack → |
| Seating restrictions | Unaccompanied minors cannot travel with a pet. |
| Routes & cargo | Domestic flights only, in the cabin — Southwest carries no pets in the cargo compartment. |
Source: official Southwest Airlines pet policy · verified 2026-09-24 · how Southwest Airlines ranks on fee and space →
Carriers that fit Southwest Airlines
Matched to Southwest Airlines's published 18 × 10.5 × 10 in limit (height checked strictly; footprint may rotate). See the full Southwest Airlines carrier shortlist →
Affiliate link — we may earn a small commission at no extra cost to you. It never changes our specs or which carriers we list.
This table ranks by Southwest Airlines’s size limit — not by your pet. The weight under each carrier is what that size is rated to hold. A bag can clear the airline and still be the wrong size for the animal, which is the most common reason one goes back — measure your pet first →
| Carrier | Size | Fit | Buy |
|---|---|---|---|
Sherpa Original Deluxe (Small) up to ~8 lb · max pet 13″ long × 7.5″ tall | 15 × 10 × 8.5 in | Fits 0.5" spare | See on Amazon → |
Petmate Soft-Sided Kennel Cab (Medium) up to ~10 lb | 17 × 10 × 10 in | Exact fit 0" spare | See on Amazon → |
Mr. Peanut's Gold Series Mini (Low-Profile) up to ~15 lb | 17 × 11 × 9 in | Squeezes — 0.5" over | See on Amazon → |
Mr. Peanut's Gold Series Standard (Expandable) up to ~20 lb | 18 × 11 × 10 in | Squeezes — 0.5" over | See on Amazon → |
11 carriers too big for Southwest Airlines
Sleepypod Atom up to ~12 lb | 17 × 8.5 × 10.5 in | Too tall (10.5" > 10") | View on Amazon |
Bergan Comfort Carrier (Small) pet size not published | 16 × 8 × 11 in | Too tall (11" > 10") | View on Amazon |
Sherpa Original Deluxe (Medium) up to ~16 lb · max pet 16″ long × 9.5″ tall | 17 × 11 × 10.5 in | Too big | View on Amazon |
Sleepypod Air up to ~18 lb | 22 × 10.5 × 10.5 in | Too big | View on Amazon |
Diggs Passenger pet size not published · Diggs discontinued this carrier — link goes to similar carriers | 17 × 12 × 10.5 in | Too big | Compare similar on Amazon → |
ibiyaya JetPaw Expandable Backpack up to ~17 lb | 18 × 12 × 10.5 in | Too big | View on Amazon |
Away The Pet Carrier pets up to ~18 lb | 18.7 × 10.8 × 10.75 in | Too big | Compare similar on Amazon → |
Petsfit (Medium) Expandable Soft-Sided up to ~13 lb | 17 × 11 × 11 in | Too big | View on Amazon |
Frisco Premium Airline-Compliant Carrier up to ~22 lb | 18 × 11 × 11 in | Too big | Compare similar on Amazon → |
Sherpa Original Deluxe (Large) up to ~22 lb · max pet 18″ long × 10.5″ tall | 19 × 11.75 × 11.5 in | Too big | View on Amazon |
SturdiBag Pro (Large, Flexible Height) pet size not published | 18 × 11.5 × 11.5 in | Too big | View on Amazon |
How to confirm your actual under-seat space
Southwest Airlines's number is its published maximum, not a guarantee for your exact seat. Before you buy or fly:
- Check which aircraft operates your flight (in your booking or on a seat-map site).
- Avoid bulkhead and exit rows — bulkheads have no under-seat storage and most airlines ban pets there — and check this airline's seat rules above.
- Call Southwest Airlines to confirm under-seat dimensions for that aircraft, or
- Choose a collapsible / flexible-height carrier that adapts to a tighter space.
More airlines: Air Canada · Alaska Airlines · Allegiant Air · American Airlines · Breeze Airways · Delta Air Lines · Frontier Airlines · United Airlines · Volaris · all →
Common questions
What size pet carrier does Southwest Airlines allow in the cabin?
Southwest Airlines's recommended maximum in-cabin carrier is 18 × 10.5 × 10 in. It must fit fully under the seat in front of you. Source: the Southwest Airlines pet policy.
How much does Southwest Airlines charge for an in-cabin pet?
$125 each way (US mainland); $35 between the Hawaiian Islands. Always confirm the current fee on the official Southwest Airlines pet page before you fly.
Which pet carriers fit Southwest Airlines?
2 of the 15 carriers we track clear Southwest Airlines's published 18 × 10.5 × 10 in. The roomiest is the Sherpa Original Deluxe (Small), with 0.5" to spare on its tightest dimension. The heaviest pet any carrier that clears Southwest Airlines is rated for is 10 lb. Full shortlist: /fits/southwest/.
Does Southwest Airlines require a soft-sided pet carrier?
Southwest Airlines recommends soft-sided but allows a hard-sided kennel within its published limit. Height is what rules carriers out: Southwest Airlines publishes 10", against 13" at the most generous airline we track.
How many pets can I bring in the cabin on Southwest Airlines?
1 carrier per passenger; 2 same-species pets may share one compliant carrier. Species accepted: cats, dogs. Space is limited — Southwest recommends reserving in advance by calling; the Pet Fare is paid at the Southwest ticket counter and is refunded if you cancel