The Guide to Southwest Airlines’ Infant Policy

On Southwest, children under 2 can travel on a parent's lap. Older children require their own ticket and seat.
Profile photo of Alisha McDarris
Written by Alisha McDarris
Mother and two children wait patiently in an airport terminal

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Flying with small children, especially babies, can be extra stressful. There’s often more to bring with you when you fly and more preparations to make beforehand, and many airlines have different policies when it comes to traveling with an infant.

Here’s everything you need to know about the Southwest Airlines infant policy so you can travel prepared.

Flying Southwest with an infant: Age restrictions

If you’re traveling with Southwest Airlines with a baby, a lap child or lap infant is at least 14 days old, but under 2 years old. They will not be occupying their own seat, but spending the duration of the flight on an adult’s lap. A child 2 years or older will need their own ticket and their own seat.

Because there’s an age restriction, you may have to prove how old your child is, so bring along an original or photocopy of either a birth certificate, passport, or government-issued ID card. A screenshot or digital copy won’t be accepted.

If you’re asked to prove the baby’s age at any point in the trip and you can’t, you may be forced to purchase a full-price ticket. However, after you return home, you can submit valid proof of age to Southwest via email and request a refund.

Southwest baby policy: Fees and boarding passes

The Southwest infant policy doesn’t require babies to have their own boarding pass, but they will need a boarding verification document, which can be printed out at a check-in kiosk or check-in counter on the day of travel. It's definitely not a bad idea to arrive a few minutes early to the airport to make sure you have everything you need in hand before you head through security.

The good news is that lap infants travel free on domestic flights, which make up the bulk of Southwest routes. On international flights, taxes and fees will likely be imposed and a more official ticket issued for your child.

Flying with an infant on Southwest: How to book

First, you’ll need to let the airline know you’ll be carrying an infant. To do so, search for flights as usual on, but when you select how many passengers will be traveling, make sure to select the number of lap infants traveling in addition to adults.

After you select your flights, when you get to the “who’s traveling” section, type in all the adults’ info as well as the child’s.

If you plan to book a flight for you and a lap infant with Rapid Rewards points, you’ll have to call the airline to do so. You'll also need to call or visit a Southwest agent at the airport to make changes to a reservation that includes a lap child after you’ve completed the booking.

As long as you're flying domestically, you can add a lap child to an existing reservation at a self-service kiosk at the airport. You can also update the baby’s date of birth, gender and name, as well as print a boarding document at a kiosk.

Flying with an infant on Southwest while breastfeeding

Nursing mothers will be pleased to know that in addition to the typical carry-on allowance (one carry-on and one personal item), those who are breastfeeding may carry an extra bag for a breast pump and breast milk.

Do keep in mind, though, that there aren’t typically outlets on board Southwest planes, so you may not be able to use electric breast pumps.

As for how much breast milk or liquid formula you can carry onboard, TSA considers the liquids medically necessary, so you can travel with more than the typical 3.4 ounces per container. Just let the TSA agents know you’re traveling with nursing liquid and they may have you remove them from your bag to be screened separately.

Boarding tips for flying Southwest with an infant

Since there are no assigned seats on Southwest flights, those with young children or lap children will want to be at the gate a few minutes before the start of boarding so they can board the plane together during family boarding.

This happens after boarding group A is called and allows up to two adults to board with small children — at least one has to be 6 or younger. This provides families with a few more precious seconds to get situated and a better chance at securing seats together if you’re in boarding group B or C.

Bottom line

The Southwest Airlines infant policy is straightforward from booking to boarding. You’ll just need to ensure your lap child is included on your reservation, bring all the proper documentation, take advantage of the airline’s unique boarding system and then enjoy the journey.

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