Flying With a Baby on Southwest
Southwest publishes more detail on flying with an infant than any other US carrier — including two rules that surprise people.
By Ryder M. · Published September 27, 2026 · Last reviewed
The short answer
Southwest carries one lap child per adult, over 14 days and under 2, free domestically — with paper government-issued ID as the only accepted proof of age. One stroller and one car seat are free per ticketed customer. A lap child may not check or carry on any baggage, and a carrier cannot be worn during taxi, takeoff or landing.
The published rules
| Item | What Southwest publishes |
|---|---|
| Lap child age | Over 14 days and under 2 years, not occupying a seat, traveling with an adult 18 or older |
| How many | One lap child per adult |
| Cost | Free of charge domestically |
| Proof of age | Original or photocopied government-issued ID only — passport, birth certificate or photo ID card. Screenshots, photos and immunization records are not accepted |
| Lap child baggage | A lap child may not check or carry on any baggage |
| Stroller and car seat | One stroller and one car seat free per ticketed customer, at curb, ticket counter or gate |
| Gate-checked items | Claimed at the baggage claim area on arrival at the final destination |
| Portable cribs and pack-and-plays | Treated as regular baggage, subject to standard checked baggage policies |
| Baby carriers | Cannot be used for taxi, takeoff and landing per FAA safety regulations |
| Car seat placement | Cannot be placed in an aisle seat |
Each row is quoted or closely paraphrased from southwest.com, read 2026-09-27 — see Sources for the exact pages.
The two rules that catch people out
Paper ID, not a photo of it. Southwest is unusually specific here: original or photocopied government-issued identification is the only accepted proof that a child qualifies as a lap child, and it publishes that electronic versions such as screenshots and photos are not accepted (southwest.com, read 2026-09-27). Print the birth certificate. A photo on your phone is the version that does not work.
The lap child has no baggage allowance. “A lap child may not check or carry on any baggage” (southwest.com, read 2026-09-27). The internet is full of confident claims that a diaper bag travels free because the baby is traveling; on Southwest, that is not what the policy says. Plan the diaper bag as your own personal item — see does a diaper bag count as a carry-on.
Where the free allowance actually is
Strollers and car seats. Southwest publishes one of each per ticketed customer, free, checkable at the curb, the ticket counter or the gate (southwest.com, read 2026-09-27). That is real and generous, and it is the allowance families under-use while trying to cram everything into a diaper bag.
One detail to note: gate-checked items are claimed at baggage claim at the final destination, not at the arrival gate. If you were counting on the stroller at a connection, that is the sentence that matters. Our gate-check guide covers it.
The carrier rule
Southwest is the clearest US carrier on this and the wording is worth knowing: baby carriers and wraps for babywearing, or any device that secures a child to the body or lap of another person, cannot be used for taxi, takeoff and landing per FAA safety regulations. You hold the baby in your arms for those phases and can re-clip at cruise. Full sequence in our carrier on a plane guide.
For the whole trip, start at our flying with a baby hub, or compare with Delta, American and United.
Questions parents actually ask
What age can a baby fly on Southwest?
Southwest publishes that one child over 14 days and under 2 years of age, not occupying a seat, may be carried as a lap child when traveling with an adult 18 or older. Each adult may travel with one lap child, and a lap child is carried free of charge domestically.
What ID do I need for a lap child on Southwest?
Southwest accepts original or photocopied government-issued identification as the only valid proof that a child is under two — a passport, a birth certificate, or a government-issued photo ID card. It publishes that electronic versions such as screenshots, photos or immunization records are not accepted. Bring the paper.
Can a lap child on Southwest have their own bag?
No. Southwest publishes plainly that a lap child may not check or carry on any baggage. If you were planning on an extra allowance because the baby is traveling, this is the rule that contradicts it.
Is the stroller free on Southwest?
Yes. Southwest publishes that each ticketed customer may check one stroller and one car seat free of charge, at the curb where curbside check-in is available, at the ticket counter, or at the gate. Items checked at the gate are claimed at baggage claim at the final destination.
Can I wear my baby in a carrier during takeoff on Southwest?
No. Southwest publishes that baby carriers and wraps, or any device that secures a child to the body or lap of another person, cannot be used for taxi, takeoff and landing per FAA safety regulations.
Sources
- Southwest Airlines — traveling with an infant — read 2026-09-27
- Southwest Airlines — stroller and child items policy — read 2026-09-27
- Southwest Airlines — lap child documentation — read 2026-09-27
- Southwest Airlines — which child restraint systems are accepted onboard — read 2026-09-27
- FAA — does the FAA require children on commercial flights to be in child restraint systems? — read 2026-09-27
Every figure on this page traces to one of the sources above. Airline policies and manufacturer specs change without notice — check the primary source before you rely on a number.
Read next
- Flying With a Baby
Airline by airline: lap infants, bassinets, gate checks and what you are allowed to carry on.
- Flying With a Baby on Delta
Lap infants free within the US, FAA-approved seats or a CARES harness, and SkyCot limits of 25 lb and 26 in.
- Flying With a Baby on American Airlines
Lap infants under 2, a 20 lb carry-on stroller limit, a free infant checked bag, and bassinets on 777 and 787 only.
- Gate-Checking a Stroller
What gate check means, what the airlines publish, where the stroller comes back, and how to stop it arriving broken.
- Can You Wear a Baby Carrier on a Plane?
Yes at cruise, no during taxi, takeoff and landing. The published rule, why it exists, and what to do instead.
More in Flying With a Baby, or start from the front page.