$28 Cheap Flights to Southwest Illinois, IL

View $28 flight on Wed, Jun 17, 2026Opens in a new window

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How much is the cheapest flight to Southwest Illinois?

Prices were available within the past 7 days and start at $28 for one-way flights and $56 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Sat, May 23 - Sun, May 24
DFW
Dallas
STL
St. Louis
$68 Roundtrip, just found
$68
Roundtrip
just found
Select Frontier Airlines flight, departing Sat, May 23 from Dallas to St. Louis, returning Sun, May 24, priced at $68 just found
American Airlines
Tue, May 19 - Wed, May 27
ORD
Chicago
STL
St. Louis
$97 Roundtrip, found 5 hours ago
$97
Roundtrip
found 5 hours ago
Select American Airlines flight, departing Tue, May 19 from Chicago to St. Louis, returning Wed, May 27, priced at $97 found 5 hours ago
United
Tue, May 19 - Wed, May 27
ORD
Chicago
STL
St. Louis
$97 Roundtrip, found 5 hours ago
$97
Roundtrip
found 5 hours ago
Select United flight, departing Tue, May 19 from Chicago to St. Louis, returning Wed, May 27, priced at $97 found 5 hours ago
Southwest Airlines
Tue, May 19 - Wed, May 27
ORD
Chicago
STL
St. Louis
$117 Roundtrip, found 5 hours ago
$117
Roundtrip
found 5 hours ago
Select Southwest Airlines flight, departing Tue, May 19 from Chicago to St. Louis, returning Wed, May 27, priced at $117 found 5 hours ago
Contour Airlines
Tue, Apr 28 - Sat, May 2
ORD
Chicago
CGI
Cape Girardeau
$138 Roundtrip, just found
$138
Roundtrip
just found
Select Contour Airlines flight, departing Tue, Apr 28 from Chicago to Cape Girardeau, returning Sat, May 2, priced at $138 just found

Alternative airports

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Flights from $325
STL
Lambert-St. Louis Intl.
Cheapest
Flights from $325

Frequently asked questions

What month is the cheapest to fly to Southwest Illinois?
The cheapest month to fly to Southwest Illinois is May when there's less demand. Off-peak months are often when you'll find cheap fares. To save money, steer clear of flying during school breaks and public holidays.
Which US cities have the cheapest flights to Southwest Illinois?
Generally, New York, Washington and Dallas offer cheap flights to Southwest Illinois. However, flexibility is the secret to getting the best prices. Book midweek or during the off-peak season to keep costs to a minimum.
Which US cities fly direct to Southwest Illinois?
You can fly to Southwest Illinois without any stops from 150 US destinations. To find a nonstop route, use the "Direct flights only" filter when organizing your flights to Southwest Illinois on Expedia. Then, explore the options and pick the best departure out of any of these cities:

  • New York
  • Washington
  • Dallas
  • Boston
  • Phoenix

How to find a cheap flight to Southwest Illinois?
Book your trip early to increase your chances of finding cheap flights to Southwest Illinois. Also, consider visiting during off-peak months like December and January. If you fly on a Thursday, you can save 16% on average compared to those departing on a Sunday.* Save time searching every day and track your flight prices using the Expedia app. We'll update you when fares change.*Best day of the week to book, depart and ideal booking window recommendations based on average round-trip ticket prices for January through August 2023, sourced from Airline Reporting Corporation's (ARC) global airline sales database. Percentages noted are averages.
How to get a cheap last-minute flight to Southwest Illinois?
Being flexible with your travel plans can help you find last-minute deals on cheap flights to Southwest Illinois. To view all the available options, try exploring different ticket types, tweaking your Southwest Illinois trip dates, jetting out of an alternative airport or using another airline.
How far in advance should I book a flight to Southwest Illinois?
To pick up the best deals on domestic journeys, book your flight to Southwest Illinois 28 days ahead of your travel dates. For international flights, it's between two and four months in advance. This improves your chances of locking in the departure dates and seats you want.**Best day of the week to book, depart and ideal booking window recommendations based on average round-trip ticket prices for January through August 2023, sourced from Airline Reporting Corporation's (ARC) global airline sales database. Percentages noted are averages.
Which day of the week is the cheapest day to buy a plane ticket to Southwest Illinois?
Sundays are usually the best day to book a cheap flight to Southwest Illinois, where you can save 8% on average compared to a Friday. If you decide to buy tickets on a Friday, expect to spend more as this is often the most expensive day.**Best day of the week to book, depart and ideal booking window recommendations based on average round-trip ticket prices for January through August 2023, sourced from Airline Reporting Corporation's (ARC) global airline sales database. Percentages noted are averages.
Which airlines fly to Southwest Illinois?
Choose the window or aisle seat and head to Southwest Illinois with one of these reputable airlines:

  • American Airlines - 1,079 flights to Southwest Illinois each month, including 927 flights to Lambert-St. Louis Intl. Airport (STL) per month.
  • Delta Air Lines - 723 flights to Southwest Illinois each month, including 637 flights to Lambert-St. Louis Intl. Airport (STL) per month.

Where do you fly into Southwest Illinois?
When flying to Southwest Illinois, the main airport to arrive at is Williamson County Regional Airport (MWA). You can also jet into nearby hubs like Lambert-St. Louis Intl. Airport (STL), MidAmerica-St. Louis Airport (BLV) or Mount Vernon, IL (MVN-Mount Vernon Outland). Another possibility to think about when you fly to Southwest Illinois is St. Louis Downtown Airport (CPS).
Can I save money by booking a Southwest Illinois trip package?
It's possible to save hundreds of dollars if you choose a Southwest Illinois flight and hotel package deal on Expedia. And you'll save time and hassle by having all your travel arrangements in one place. Try bundling your flight and hotel with add-ons like tours and activities for your own personalized Southwest Illinois vacation.
Can I change or cancel my flight to Southwest Illinois?
If you reserved your flight to Southwest Illinois within the last 24 hours, you can usually change or cancel it for free. After that, extra charges may apply depending on the airline's rules and restrictions. For more information, check out our Customer Service Portal. Remember that some flights are non-refundable, so you may receive a credit for a future trip rather than a direct refund. When browsing Expedia, select the "No cancel fee" or "Changes included" filters to find tickets with flexible change policies.

*Flight schedules are subject to change.

*Available to One Key members.

 

Travel information

Destination airport
Lambert-St. Louis Intl.
Destination airport IATA code
STL
Destination city name
St. Louis
Roundtrip price
$97

Trending flights to Southwest Illinois

Prices were available within the past 7 days and start at $28 for one-way flights and $56 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Wed, Jun 17 - Tue, Jun 23
DEN
Denver
STL
St. Louis
$56 Roundtrip, just found
$56
Roundtrip
just found
Select Frontier Airlines flight, departing Wed, Jun 17 from Denver to St. Louis, returning Tue, Jun 23, priced at $56 just found

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