Southwest Customer of Size Policy: Extra Seats and Refunds
How Southwest's customer of size policy works: when you need a second seat, how to book it with XS, what happens at the gate, and the 90-day refund rules.
The armrest will not come down, and your hip is in the next seat before the plane has left the gate. Buying one seat and planning to sort it out at the airport works only some of the time: Southwest gives a free extra seat at the airport only when the seats next to you are open, and on a sold-out flight it moves you to a later one. Below is how to tell whether you need the second seat, how to book it, what the airport can and cannot do, and how to get the money back afterwards.
The short answer
| Your situation | What Southwest’s pages say |
|---|---|
| You spill past the armrest | You may need two adjacent seats; the armrest is the boundary |
| You book the second seat ahead | Recommended; name it with XS as the second passenger |
| You did not book it | A free extra seat at the airport if adjacent seats are open; otherwise a later flight |
| You flew with two seats | Refund request within 90 days of travel, if the flight left with an open seat (or with space-available pass travelers aboard) and both seats are in the same fare class |
| You booked through a partner airline | Buy the extra seat from the partner; it is non-refundable |
Do you need a second seat?
Southwest’s Customer of Size policy puts it in one line: “Customers who encroach upon the neighboring seat(s) may need to occupy two adjacent seats.” It also says “The armrest is considered to be the definitive boundary between seats.” So the policy’s test is the armrest, not a clothing size. Southwest also says it “may determine, in its sole discretion, that an additional seat is necessary for safety purposes.”
The seats are not all the same width. Southwest’s seat specifications list:
| Aircraft | Seat width | Movable aisle armrests |
|---|---|---|
| 737-700 | 15.5 to 17.0 inches | All rows |
| 737-800 and 737 MAX 8 | 15.5 to 17.8 inches | All rows except the front bulkhead row |
The table gives only a narrowest and a widest figure for each aircraft, so you cannot tell from it which width your seat will be. One rough check before you book (our suggestion): sit on a hard, flat chair and have someone measure straight across your widest point, hips or thighs. If that number is over 17.8 inches, the widest seat on the table, plan on the second seat. Between 15.5 and 17.8 inches you may or may not fit, depending on the seat; buying the second seat up front is the safer route, and it can be refunded if the flight meets the conditions further down (our suggestion).
A movable aisle armrest does not change the rule (our reading): the armrest beside your neighbor is still the boundary.
How to book the second seat
Southwest asks you to buy it when you book. Its policy says “we strongly recommend that you purchase the seat prior to travel to ensure that adjacent seats are available.” Its booking steps for Southwest.com work like this:
- In the Passengers field, choose the total number of seats you need as adults: two for one extra seat.
- Go through the Select Flight and Trip & Price Details pages as usual.
- Enter your own name as Passenger One.
- Enter the extra seat as Passenger Two, with XS added as a middle name before your last name. Southwest’s example: “A Passenger named Tom Smith would designate Passenger One as ‘Tom Smith,’ and Passenger Two as ‘Tom XS Smith’”. If you have a middle name, keep it and put XS after it: Tom James XS Smith.
- Choose two seats next to each other. The policy says “Depending on your fare type, your fare may include the ability to choose your seats when booking.” If seat selection is not offered while you book, it asks you to “please contact us as soon as possible” “so we can assist you in assigning adjacent seats.” The policy section we read gives no phone number for this; use the contact options on Southwest’s Help Center.
The same page lists five mistakes to avoid: the extra seat goes second, not first; no XS in the first name field; do not leave your middle name off the extra seat; no XS before the middle name; a space between XS and your last name.
Two more rules from the policy. If adjacent seats are not available on your flight or in your fare class when you contact Southwest, it says “we’ll rebook you on another flight where adjacent seats are available.” And “Extra seats may not be purchased solely to keep the adjacent seat empty.”
If your trip includes a partner airline, Southwest says to contact that partner to buy the extra seat. If you booked a Getaways by Southwest vacation, contact Getaways to add it.
On the day, with both seats booked, check in online or at a kiosk to get your boarding pass and the “seat reserved document”, then “Board in your assigned group.”
If you get to the airport with one seat
Southwest changed this policy in January 2026 and again in late May. From January, Southwest required plus-size passengers to buy the second seat before traveling; in late May it changed that, and agents at the airport can now offer an additional seat at no extra cost when one is free next to you.
Southwest’s airport page sets out what happens if it decides you need the extra seat:
- Adjacent seats open: “You’ll be accommodated with a complimentary extra seat, but only if adjacent seats are available.” Southwest adds: “This may result in a change of seat type, including a lower category of seat.” If you paid for an Extra Legroom seat, that could mean losing it (our reading).
- Sold out, or no adjacent seats: Southwest rebooks you “on an alternate flight to your destination on which adjacent seats are available.”
- After boarding: the policy says “If this determination is made after boarding, you may need to deplane for rebooking.”
Tell the agent at the ticket counter or gate as early as you can, so there is time to find adjacent seats or rebook (our suggestion). The free seat is a fallback, not a plan, and it is least likely on a full flight. Southwest says it plainly: “To avoid being rebooked, we strongly encourage you to purchase your second seat when you make your initial reservation.”
On board: the seatbelt extension
If the lap belt does not reach, ask the flight attendant for an extension once you are on board. The policy says “Only one seatbelt extension per Passenger is approved for use onboard the aircraft,” “and the seatbelt extension must be provided by Southwest Airlines®.” It adds: “A seatbelt extension cannot be used by a Passenger seated in an exit seat.” So do not pick an exit row if you think you will need one. A seat belt buckle extender for your car is a separate product and may not fit an aircraft belt; on the plane, use the one the flight attendant gives you.
Getting the second seat refunded
You can ask for the money back on the extra seat after you fly. Southwest’s refund page says “We will refund an extra seat purchased to accommodate a Customer of size provided the following conditions apply:”
- “The flight(s) must depart with at least one open seat (or with Passengers traveling on space available passes)”
- “Both seats should be purchased in the same fare class (i.e., Choice, Choice Preferred, Choice Extra, or Basic)”
Then the deadline: “The refund request must be made within 90 days of your date of travel.” The request goes through the refund form linked from that page.
Two things follow from those conditions. Book both seats in the same fare class (Basic, Choice, Choice Preferred or Choice Extra); booking them together in one reservation, as above, does this (our reading). And if every seat leaves occupied, with no open seat and no one on a space-available pass, the extra seat is not refunded. The exception is partner travel: “An additional seat purchased by a Customer traveling on an itinerary that includes a partner carrier is non-refundable.”
Before you book
- Read the policy page on the day you book. It changed in January 2026 and again in late May; what is above is the version we read on 29 October 2026.
- Book both seats at once, in the same fare class, with the XS name on the second passenger.
- Skip the exit row if you may need a seatbelt extension.
- Keep the refund date: 90 days from your date of travel.
For seats on the ground, our seating guides list the published seat widths and weight limits of chairs, recliners and more.
Where these numbers come from
The rules, quotes, seat widths and refund conditions are from Southwest’s Help Center pages on its Customer of Size policy, booking, airport experience, second-seat refunds and airplane specifications, read on 29 October 2026. The dates of the January and May 2026 changes are from ABC News’s report of 28 May 2026.
Frequently asked questions
Does Southwest still give a free extra seat to a customer of size?
At the airport, only when adjacent seats are open; a second seat bought ahead can be refunded after travel if Southwest's refund conditions are met. Southwest's policy page says a customer who did not buy a second seat and is found to need one will be given a complimentary extra seat, but only if adjacent seats are available, which may mean a lower category of seat. If the flight is sold out or no adjacent seats are open, Southwest rebooks you on a later flight that has them. Buying the second seat when you book avoids that.
How wide is a Southwest seat?
Southwest's airplane specifications page lists seat widths of 15.5 to 17.0 inches on its 737-700 and 15.5 to 17.8 inches on its 737-800 and 737 MAX 8. The table gives a narrowest and a widest figure for each aircraft, not a width per seat. Southwest's policy treats the armrest as the boundary between seats.
How do I get my second Southwest seat refunded?
Use the refund request form on Southwest's Help Center within 90 days of your date of travel. Southwest's refund page lists two conditions: the flight must depart with at least one open seat (or with passengers on space-available passes), and both seats should be bought in the same fare class. A second seat bought on an itinerary that includes a partner carrier is non-refundable.
Can I bring my own seat belt extender on Southwest?
Southwest's policy page says only one seatbelt extension per passenger is approved for use on the aircraft and that it must be provided by Southwest Airlines, so ask the flight attendant for one once you are on board. An extension cannot be used by a passenger seated in an exit seat.
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