Flying Southwest Airlines with Kids: Free Bags, Family Boarding & Lap Infant

Per Southwest Airlines' published policy, infants under 24 months at time of travel may fly as lap infants at no base fare on US domestic routes. On Southwest's international routes to the Caribbean, Mexico, and Central America, lap infants also travel free of a base fare, though taxes and government-imposed fees may apply depending on the destination and itinerary. A minimum age of 14 days applies — Per Southwest Airlines' published policy, southwest does not accept newborns under 14 days for air travel. The infant's age is determined on the date of each flight segment, so if your child turns 2 during a round-trip, the return leg requires a purchased seat at the full adult fare. Always verify the total fee breakdown for international bookings at southwest.com before confirming.

Per Southwest Airlines' published policy, infants under 24 months are not required to have their own seat and may travel as lap infants at no base fare. However, the FAA strongly recommends that every child under 2 fly in an approved child restraint system (CRS) secured in their own seat, as lap-held infants are not restrained during turbulence. If you choose to purchase a seat for your infant, the full adult fare applies — Per Southwest Airlines' published policy, southwest does not offer a discounted infant seat fare. The purchased seat must be used with an FAA-approved CRS bearing the official approval label. In-cabin use of the car seat requires that FAA label to be clearly visible to flight crew. Always verify current seat-purchase options at southwest.com.

Per Southwest Airlines' published policy, bassinets are not offered on any Southwest aircraft. The carrier operates an all-Boeing 737 narrow-body fleet — the 737-700, 737-800, and 737 MAX 8 — none of which are equipped with bulkhead bassinet attachment points. Additionally, Southwest's current open-seating model makes pre-assigned bassinet rows structurally impractical. Parents of infants who need in-flight sleeping support should bring a soft-structured carrier or baby carrier for use during the flight. For families who specifically need bassinet availability, long-haul international carriers such as Emirates, Qatar Airways, or Singapore Airlines offer reservable bassinets on their wide-body aircraft — a fundamentally different product category from Southwest's domestic and near-international network.

Per Southwest Airlines' published Bags Fly Free policy, every ticketed passenger — including children with their own purchased seat — receives 2 free checked bags weighing up to 50 lb (approximately 23 kg) each. This applies to every fare type on every Southwest route. A family of four with two ticketed children can check up to 8 bags at no cost, saving USD 200–400 or more compared with most US legacy carriers or ULCCs that charge USD 25–45 per bag per direction. Lap infants (no purchased seat) do not receive their own checked-bag allowance but benefit from the diaper bag exemption, which does not count against the accompanying adult's carry-on allowance. Always verify the baggage summary at southwest.com before your trip.

Per Southwest Airlines' published policy, unaccompanied minor service is available for children ages 5 through 17. For children ages 5 to 11, the service is mandatory — these children may not travel alone without the UM program. For children ages 12 to 17, the service is optional. The fee is USD 100 each way. A critical restriction applies: Southwest's UM service is limited to non-stop flights only — connecting itineraries are not accepted under any circumstances. Booking must be completed by phone through Southwest's official reservations channel; online self-service is not available for UM bookings. A responsible adult must accompany the child through check-in and remain at the airport until the flight departs; a receiving adult with matching government-issued photo ID must be present at the destination before the child is released. Always verify current UM rules at southwest.com before booking.

Per Southwest Airlines' published policy, family boarding is available for parties traveling with at least one child age 6 or under. The boarding group is called after the A group (which includes EarlyBird purchasers and business-select customers) and before the B group begins. This age threshold — 6 and under — is notably broader than the US-industry norm, where most carriers (including JetBlue) pre-board only families with children under 2. The practical result is that parents of kindergarten-age children can use the family boarding window rather than being separated into general boarding. As of 2026, Southwest is transitioning to an assigned-seating model; the family-boarding mechanic is expected to be preserved in some form, but verify the current boarding procedure at southwest.com for your specific travel date.

Per Southwest Airlines' published Bags Fly Free policy, no fee applies to the first 2 checked bags for any ticketed passenger, including ticketed children. Unlike Delta Air Lines, United Airlines, American Airlines, Frontier Airlines, or Spirit Airlines — which charge USD 30–99 per bag per direction on most economy fares — Southwest's checked-bag allowance is included in every fare type at no additional cost. Children traveling as ticketed passengers (age 2 and older with their own purchased seat) receive the full 2-bag allowance. Lap infants do not receive a separate checked-bag allowance but the diaper bag is exempt from the parent's carry-on limit. This Bags Fly Free policy is the primary family-cost differentiator Southwest holds versus the rest of the US mid-tier and ULCC market. Verify baggage policies at southwest.com before booking.

According to Southwest Airlines' published announcements, the carrier is transitioning from its longstanding open-seating model to assigned seating in 2026, with the addition of extra-legroom seats. For families, the open-seating model has historically meant that adjacent seat selection depended on boarding position — family boarding between groups A and B gave families a practical advantage but no formal guarantee of sitting together. Under assigned seating, families will be able to select seats at the time of booking, which should eliminate the uncertainty about adjacency. Southwest has published that the family-boarding mechanic will be preserved in some capacity through the transition. The Bags Fly Free checked-bag policy is confirmed to remain unchanged. For any booking with travel dates that may fall during or after the 2026 transition, verify the current seating model and boarding procedure directly at southwest.com before purchasing.

Per Southwest Airlines' published booking information, lap infants can be added to domestic bookings through the Manage Reservations tool at southwest.com after the adult ticket is purchased. This is more convenient than many US carriers that require a phone call for all infant additions. However, there is a documented edge case: some international bookings — particularly to Mexico — have known issues with the online infant-add tool. If you encounter an error during the online process for a Mexico or Caribbean itinerary, note your booking confirmation number and contact Southwest Airlines through its official website or reservations channels to complete the addition. Always verify the updated booking confirmation email before travel to confirm the infant appears on the reservation manifest.

According to the US Department of Transportation's published Family Seating Dashboard — which tracks US airline commitments to seat children adjacent to accompanying adults without a fee — Southwest Airlines is on the commitment list as of 2026. The DOT initiative identifies carriers that have publicly committed to seating children near an accompanying adult without charging an additional seat-selection fee. Southwest's inclusion on the dashboard reflects its overall family-seating approach, supported by the family-boarding policy that enables families with children age 6 and under to board early and self-select adjacent seats. With the planned 2026 transition to assigned seating, Southwest's commitment under the DOT framework is expected to continue under the new model. Always verify the current DOT dashboard status at transportation.gov and Southwest's current seat-selection policies at southwest.com.

Per Southwest Airlines' published policy, one stroller and one child restraint system (car seat) per ticketed child are accepted free of charge at either the ticket counter or at the gate. These items are in addition to the standard 2 free checked bags per passenger under the Bags Fly Free policy — they do not consume any portion of the baggage allowance. The all-Boeing 737 fleet means jet-bridge return is available at most Southwest stations, so parents can typically collect strollers at the jet bridge upon landing rather than at baggage claim. If using a car seat in-cabin during the flight, an FAA-approval label must be visibly affixed to the seat. For gate check, no size or weight restriction is published for strollers. Booster seats without a built-in harness are not FAA-approved for in-cabin use but are accepted for gate-checked transport at no fee. Verify current policies at southwest.com before travel.