In-cabin pet carriers that fit Southwest Airlines
The carriers from our list that clear Southwest Airlines' official 18 × 10.5 × 10 in under-seat limit — sorted best-fit first, with the ones that squeeze in when collapsed flagged.
Short answer: 4 of the 15 carriers we track fit Southwest Airlines' 18 × 10.5 × 10 in limit: 1 with room to spare on every side, 1 with no room to spare on at least one side and 2 only when collapsed or squeezed a little. 11 are too big.
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| Carrier | Size | Fit | Buy |
|---|---|---|---|
Sherpa Original Deluxe (Small) up to ~8 lb · max pet 13″ long × 7.5″ tall 15 × 10 × 8.5 in is within 18 × 10.5 × 10 in — 3" spare on length, 0.5" on width, 1.5" on height. Tightest margin is 0.5", so measure before you fly. · collapsible/flex · full fit detail → | 15 × 10 × 8.5 in | Fits | See on Amazon → |
 Petmate Soft-Sided Kennel Cab (Medium) up to ~10 lb 17 × 10 × 10 in is within 18 × 10.5 × 10 in — 1" spare on length, 0.5" on width, 0" on height. Tightest margin is 0", so measure before you fly. · full fit detail → | 17 × 10 × 10 in | Exact fit | See on Amazon → |
Mr. Peanut's Gold Series Mini (Low-Profile) up to ~15 lb 17 × 11 × 9 in is 0.5" over on width against a 18 × 10.5 × 10 in limit, and height clears with 1" to spare. Soft sides compress, so this usually goes under the seat — but it is over the published figure, so measure yours and be ready for an agent to check. · collapsible/flex · full fit detail → | 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 is 0.5" over on width against a 18 × 10.5 × 10 in limit, and height clears with 0" to spare. Soft sides compress, so this usually goes under the seat — but it is over the published figure, so measure yours and be ready for an agent to check. · collapsible/flex · full fit detail → | 18 × 11 × 10 in | Squeezes — 0.5" over | See on Amazon → |
Also checked, too big for Southwest Airlines: Sleepypod Atom · Bergan Comfort Carrier (Small) · Sherpa Original Deluxe (Medium) · Sleepypod Air · Diggs Passenger · ibiyaya JetPaw Expandable Backpack · Away The Pet Carrier · Petsfit (Medium) Expandable Soft-Sided · Frisco Premium Airline-Compliant Carrier · Sherpa Original Deluxe (Large) · SturdiBag Pro (Large, Flexible Height) — each one shows the exact measurement it misses by.
Every fit is against the published maximum; real under-seat space varies by aircraft (why). Full rules & fees: Southwest Airlines pet policy → · how Southwest Airlines ranks on fee and space →
Other airlines: Sun Country Airlines · Swiss International Air Lines · TAP Air Portugal · Transavia · Turkish Airlines · United Airlines
Common questions
What size pet carrier does Southwest Airlines allow in the cabin?
Southwest Airlines' published limit for a carrier under the seat in front of you is 18 × 10.5 × 10 in. Weight limit: not published. We last checked this against Southwest Airlines' own pet policy on 2026-09-24.
How many pet carriers fit Southwest Airlines' limit?
4 of the 15 carriers we track fit Southwest Airlines' 18 × 10.5 × 10 in limit: 1 with room to spare on every side, 1 with no room to spare on at least one side and 2 only when collapsed or squeezed a little. 11 are too big.
Which carriers only fit Southwest Airlines when collapsed or squeezed?
Mr. Peanut's Gold Series Mini (Low-Profile), Mr. Peanut's Gold Series Standard (Expandable). Each is over the published size until folded or pressed down, so measure yours and expect it may be checked at the gate.
Which carriers are too big for Southwest Airlines?
Sleepypod Atom, Bergan Comfort Carrier (Small), Sherpa Original Deluxe (Medium), Sleepypod Air, Diggs Passenger, ibiyaya JetPaw Expandable Backpack, Away The Pet Carrier, Petsfit (Medium) Expandable Soft-Sided, Frisco Premium Airline-Compliant Carrier, Sherpa Original Deluxe (Large), SturdiBag Pro (Large, Flexible Height). Each is over the 18 × 10.5 × 10 in limit.
How much does Southwest Airlines charge for a pet in the cabin?
$125 each way (US mainland); $35 between the Hawaiian Islands. Confirm the current fee with Southwest Airlines when you book.