Southwest's national sale takes up to 40% off base fares booked September 14 to 17 for travel October 5, 2026 to March 3, 2027, and on the flights we checked the points price fell with the cash price: Dallas to Denver dropped from $166 to $106 and from 10,500 to 6,500 points on the same seat. The blackout dates, the day-of-week rule, the change clause that forfeits the discount, and which card to pay with.
Southwest's sale banner says one thing, and the fare grid says a second thing the banner leaves out. The headline is up to 40% off base fares, booked by Wednesday night, no code. The part worth knowing is what happened when we flipped the same search to points: the points price on the same seat had dropped by about the same share.
From the sale terms on southwest.com, read September 14, 2026:
"Up to 40 percent off promotion savings valid for qualifying one-way or round trip fares booked on Southwest.com® or swabiz.com from September 14, 2026 at 12:01 a.m. Pacific Time ("PT") through September 17, 2026 11:59 p.m. PT (the "Booking Period"), and flown between October 5, 2026-March 3, 2027 (the "Travel Period")."
"Discount is automatically applied and shown as a strikethrough on the displayed base fare on eligible flights."
So there is nothing to enter. If a flight is in the sale, you see the old price struck through and the new one next to it. If you see no strikethrough, that flight is not in the sale, whatever the banner says.
We searched one adult, Dallas (Love Field) to Denver, Monday October 5, 2026, and read the nonstop flights tagged "Low fare" twice: once in dollars, once with the points toggle on. Read September 14, 2026; these are what the site displayed at that moment and they will move.
| Fare | Cash, before → after | Points, before → after |
|---|---|---|
| Basic | $166 → $106 | 10,500 → 6,500, plus $5.60 |
| Choice | $206 → $147 | 13,500 → 9,500, plus $5.60 |
| Choice Preferred | $276 → $216 | 18,500 → 14,000, plus $5.60 |
| Choice Extra | $321 → $263 | 21,500 → 17,500, plus $5.60 |
Two things fall out of that table.
The cash cut is smaller than 40% on the total you pay. On the Basic seat the price fell $60 on $166, which is 36%. The terms explain the gap: "Promotion savings are applied before government taxes and fees," and "this promotion applies to the base fare only." The 40% is on the fare underneath the taxes, and the taxes do not move.
A point buys the same amount at the sale price as it did before. Before the sale, 10,500 points stood in for $160.40 of fare after the $5.60 in taxes, about 1.5 cents a point. After it, 6,500 points stand in for $100.40, also about 1.5 cents. The sale does not change whether you should pay cash or points on Southwest. It changes the price of both by roughly the same share, so if you were going to spend points anyway, this is the cheaper week to spend them.
Not every flight on that day was in the sale. The 9:15 and 11:50 departures showed no strikethrough in either currency. The terms say why: "Discount availability may vary by destination, flight, and day of the week, and won't be available on some flights that operate during very busy travel times and holiday periods."
Quoted from the same terms. Continental U.S. travel is blacked out on:
Travel from the continental U.S. to international destinations, Hawaii, St. Thomas and Puerto Rico is blacked out November 19 to 25 and December 17 to January 5. Travel back to the continental U.S. from those places is blacked out November 27 to December 1 and December 17 to January 5. Interisland Hawaii travel is not included at all.
This is the rule most people miss, and it is in the terms in plain words.
| Route | Sale-eligible days |
|---|---|
| Within the continental U.S. | Monday through Saturday |
| Continental U.S. to Hawaii, St. Thomas, or international | Sunday through Wednesday |
| Hawaii, St. Thomas, or international back to the continental U.S. | Tuesday through Friday |
| To or from Puerto Rico | Monday through Thursday |
A Sunday flight inside the country is not in the sale. If your dates are flexible by a day, Saturday or Monday is where the discount lives.
"Changes made to the itinerary after purchase will eliminate qualification for this promotion and will result in forfeiture of any promotion savings."
Book the dates you will actually fly. The discount is also "valid on new reservations only," "not combinable with other promotions or fares," and not valid on group travel or Getaways by Southwest packages.
If you pay cash, the Southwest cards earn the most on the purchase, from our own card records: Rapid Rewards Plus earns 2x on Southwest, Premier and Premier Business earn 3x, and Priority and Performance Business earn 4x.
If you pay points and are short, two programs move to Rapid Rewards at one to one: Chase Ultimate Rewards and Bilt. Marriott Bonvoy transfers at 3 to 1 and World of Hyatt at 25 to 12, which are poor ways to get here. Transfer only what the fare needs, and only after the strikethrough is on the screen, because Rapid Rewards points do not move back.
Sale terms read from southwest.com (the booking page and the national sale page) on September 14, 2026. Fares and points prices are what the site displayed for one adult, Dallas (Love Field) to Denver, October 5, 2026, at the time of reading, and will change. Earn rates and transfer ratios are from our own card records. Not affiliated with Southwest Airlines or Chase.