Southwest Airlines is running a dated flash sale through 11:59 p.m. Pacific Time on August 13, 2026. Official terms take up to 40 percent off the base fare on select flights booked from August 10 at 12:01 a.m. PT through that cutoff, for travel between August 31, 2026, and March 3, 2027.
The nationwide sale page and the current flight-deals tile are the source. AwardWallet recapped the same book-by August 13 window and the automatic base-fare cut. The discount is not a promo code. It is not 40 percent off every seat.
- Book by: August 13, 2026, 11:59 p.m. PT.
- Fly: Select flights August 31, 2026, to March 3, 2027.
- Cut: Up to 40 percent off the base fare only.
- Where: Southwest.com, swabiz.com, or Southwest Partner Services.
- Not: Old tickets, Getaways packages, GDS bookings, or group fares.
What the official clock actually is
The booking window opened August 10 at 12:01 a.m. PT. It closes August 13 at 11:59 p.m. PT. If you are in Eastern Time, that is 2:59 a.m. on August 14. Do not treat midnight Eastern on the 13th as the end.
Travel must be flown between August 31, 2026, and March 3, 2027. A September weekend can qualify. A mid-August trip this month cannot. The sale does not pull the travel start earlier.
The discount applies before government taxes and fees. The Department of Transportation still requires the advertised total to show those add-ons. A 40 percent base-fare cut will not look like 40 percent off the checkout total. Compare the strikethrough base fare on an eligible flight, then look at the all-in number.
Seats, days, and markets are limited. Southwest says the cut will not appear on some busy and holiday flights. If the fare does not show a strikethrough on the base amount, that flight is not in the sale. Do not invent a missing code.
Blackouts and weekday rules
Continental U.S. and interisland Hawaii travel is blacked out on November 21, 24, 25, 28, and 30, December 18, 19, 23, 26, 28, and 30, 2026, and January 1, 2, 4, 15, and 18 plus February 12 and 15, 2027.
Continental U.S. travel to international points, Hawaii, Anchorage, St. Thomas, and Puerto Rico is blacked out September 3 to 8, November 19 to 25, and December 17, 2026, to January 5, 2027.
The return direction, from those points into the continental U.S., is blacked out September 3 to 8, November 27 to December 1, and December 17, 2026, to January 5, 2027.
Weekdays are also gated. Continental U.S. and interisland Hawaii sale travel is valid Monday through Saturday. Travel from the continental U.S. to Hawaii, Anchorage, St. Thomas, and international is valid Sunday through Wednesday. Travel to the continental U.S. from those points is valid Tuesday through Friday. Puerto Rico sale travel is valid Monday through Thursday.
If your holiday week sits on a blackout, stop. If your outbound day is a Sunday on a domestic-only itinerary, that day is outside the continental U.S. window. Rebuild the dates before you click.
Deep Arrival's Southwest Airlines planning page is the evergreen place to reset bags, change rules, and network pattern around a fare that only lasts two more nights.
Who should move now
If you already have a Southwest ticket, do not change it to chase this sale. Official terms say a change after purchase kills the promotion savings. A previously booked flight is also excluded. This is new reservations only.
If you can fly after August 31 on a weekday that matches the table, search now on Southwest.com or swabiz.com. Watch for the strikethrough on the base fare. If it is not there, that market is not on sale.
If you need Thanksgiving week, Christmas week, or New Year week, this sale is the wrong tool. Those dates are written out. A January 15 or February 15 trip is also written out on the domestic list.
If you were going to book through a third-party GDS, a group desk, a military or government fare, or a Getaways by Southwest vacation package, the discount is not valid. Stay on Southwest.com or swabiz.com.
| If you | What to do |
|---|---|
| Can fly Aug 31 to Mar 3 on an allowed weekday | Search Southwest.com now. Book only if the base fare shows a strikethrough. |
| Need Thanksgiving, Christmas, or New Year week | Skip this sale. Those dates are blacked out. |
| Already hold a Southwest ticket | Do not change it. A change forfeits the promotion. |
| Want a Getaways package or GDS booking | This discount does not apply. Price the package on its own terms. |
| Are in Eastern Time on August 13 | The clock dies at 2:59 a.m. ET on August 14, not midnight ET. |
- Clock: August 13, 11:59 p.m. PT is the hard end.
- Math: Up to 40 percent is off the base fare, not the taxed total.
- Days: Domestic sale days are Monday to Saturday. Sunday is out on that table.
- Changes: A post-purchase change drops the savings.
- Channels: Southwest.com, swabiz.com, Partner Services only.
How to use the next 36 hours
Search the city pair first. If no strikethrough appears on the dates you can actually fly, walk away. The sale is not a blanket coupon.
Then check the weekday table and the blackout list against both the outbound and the return. A legal outbound with an illegal return is not a sale itinerary.
Then check the all-in total against a non-sale day on the same pair. If a Tuesday after Labor Day is cheaper without needing the 40 percent label, take the cheaper legal fare. The point is the checkout number, not the badge.
Then book only if you can live with the dates. Southwest says a later change removes the promotion. Treat the itinerary as sticky unless you are willing to lose the cut.
Do not stack this with another Southwest promo, a gift card purchase, or a military or government fare. The terms say the discount is not combinable and is not valid on those special fares.
Reward travel still owes taxes and fees of at least $5.60 one way. This sale is a cash-fare base-fare cut. It is not a Rapid Rewards bonus and it is not a companion-pass shortcut.
If the landing page widget says an offer is unavailable while the flight-deals tile still shows the August 13 clock, trust the written terms and the strikethrough on a live search. If neither the tile nor a strikethrough remains, the sale is gone. Do not force a booking.
Two bags still fly free on Southwest, with weight and size limits, on a regular ticket. That perk is not the sale. Do not pay a third-party extra to chase a bag benefit you already have. Use the extra minutes to confirm the weekday table instead.
Optional products still cost extra. EarlyBird, upgraded boarding, and other add-ons sit outside the 40 percent math. Price the base itinerary first. Only then decide whether an extra is worth paying on a sale ticket you cannot cheaply change. Fares can still move until ticketed, so screenshot the strikethrough before you pay.
When does the Southwest 40 percent sale end?
August 13, 2026, at 11:59 p.m. Pacific Time. That is 2:59 a.m. Eastern on August 14.
Is every Southwest flight 40 percent off?
No. Only select flights show an automatic strikethrough on the base fare. Seats, days, and markets are limited.
Does the cut include taxes?
No. It applies to the base fare before government taxes and fees.
Can I change the ticket later and keep the sale?
No. Official terms say a change after purchase eliminates the promotion savings.
Can I use this on a trip I already booked?
No. The discount is for new reservations only and is not valid toward a previously booked flight.
