[Expired] Southwest Airlines Has Flights Starting at $49 [Book by September 18]

Updated: September 19, 2025, 7:13am CDT

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Table of Contents

Southwest Sale Details
Recap on Recent Southwest Changes
Final Thoughts

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Update:

The offer mentioned below has expired and is no longer available.

Southwest Airlines is out with a new promotion, and the airline has one-way flights starting at just $49 — but only if you book soon, as this promotion ends on September 18.

With this offer, you can travel from October 2025 to March 2026. Whether you’re flying within the U.S. mainland, to Hawaii, or to international destinations, you can score flights for a great price.

Here’s everything you need to know about Southwest’s latest promotion.

Southwest Sale Details

This sale offers $49 fares on many Southwest flights, and you don’t need a promo code to get in on this deal. You must book by September 18, 2025, at 11:59 p.m. PT. The full terms are on the promotion’s landing page. This sale applies primarily to Basic fares, but Choice fares are included on routes within Hawaii and routes to/from Cuba.

Be aware that the eligible travel dates vary by destination, and the sale only applies to flights booked directly with Southwest. Seats, days, and markets are limited, so make sure to check the full terms and conditions when booking.

Additionally, you must book at least 21 days in advance of your flight. Moreover, note that these are nonrefundable Basic fares.

Eligible travel dates are as follows:

Continental U.S.
- Travel from October 7, 2025, to March 4, 2026
- Blackout dates: November 21, 25, and 26; November 29-December 1, December 19-23, December 26-29, 2025; and January 2-4, 2026
- Travel not valid on Friday or Sunday
To Hawaii, Puerto Rico, and international destinations from the continental U.S.
- Travel from October 7, 2025, to March 4, 2026
- Blackout dates: November 20-24; December 18, 2025-January 6, 2026; and February 12-15, 2026
- Travel valid from Sunday to Wednesday (except Puerto Rico, as travel is valid Monday to Thursday)
From Hawaii, Puerto Rico, and international destinations to the continental U.S.
- Travel from September 30, 2025, to March 4, 2026
- Blackout dates: November 28-December 2; December 18, 2025-January 6, 2026; and February 20-22, 2026
- Travel valid from Tuesday to Friday (except Puerto Rico, as travel is valid Monday to Thursday)
Interisland Hawaii flights
- Travel from October 7 to November 18, 2025
- Travel valid on Tuesday and Wednesday
Between St. Thomas and the continental U.S.
- Travel from February 5 to March 4, 2026
- Blackout dates to St. Thomas: November 20-24; December 18, 2025-January 6, 2026; and February 12-15, 2026
- Blackout dates back to the continental U.S.: November 28-December 2; December 18, 2025-January 6, 2026; and February 20-22, 2026
- Travel valid from Sunday to Wednesday

Sample Fares

Here’s an example of a discounted ticket from Las Vegas (LAS) to San Francisco (SFO) that you can book for just $49 in Basic and $69 for Choice:

Southwest LAS SFO 49 fare example — Image Credit: Southwest Airlines

Remember, Southwest has an easy-to-use Low Fare Calendar to help you find the cheapest dates when your travel plans are flexible.

Since Southwest Rapid Rewards is a revenue-based program, sales also apply to flights booked using points. Unfortunately, you won’t get outsized value: Expect to get around 1.1 to 1.5 cents per point from your Rapid Rewards points.

Southwest LAS SFO points fare example — Image Credit: Southwest Airlines

If you use one of Southwest’s co-branded credit cards to pay for your tickets, you could earn 2 to 4 Rapid Rewards points per $1 spent on your Southwest purchases. These cards also have other perks like anniversary bonus points every cardmember year, EarlyBird Check-In certificates, and more.

Hot Tip:

This sale doesn’t apply to existing bookings, so if you find your same flight is now available at a lower price, you can book it and cancel your existing reservation. Here’s how to change or cancel a Southwest flight.

Recap on Recent Southwest Changes

Remember that Southwest recently introduced basic fares (to replace the previous Wanna Get Away) and ended its popular “everyone gets 2 free checked bags” policy on May 28, 2025. Now, the number of free checked bags you’ll get, if any, depends on what credit cards you hold and whether you have elite status with Southwest Airlines.

Final Thoughts

Southwest is running a flash sale on dozens of routes, offering $49 one-way base fares if you book by September 18. Remember that the eligible travel dates vary by route.

Remember that the cheapest fares now book into Southwest’s Basic fare type, and the airline applied its new baggage policy to all bookings made after May 28, 2025. That means you will not automatically qualify for free checked bags when booking the cheapest tickets, and that’s worth considering as you look at prices.