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St. Louis

$49+ Cheap flights from Illinois to St. Louis (STL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 1/7. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — STL
Oct 16 — Oct 231
Thu 10/16
Thu 10/23
1 adult, Economy
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Cheap flight deals from Illinois to St. Louis

Keep the following information in mind while searching for Illinois to St. Louis flight deals. Data was last updated September 16, 2025.

Round-trip from

$97
(Southwest)

One-way from

$49
(Southwest)

Popular in

July

Cheapest in

August

Average price

$346

Good round-trip deal

$207 or less

Good one-way deal

$110 or less
From Illinois to Lambert-St Louis
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One-way flight from Illinois to Lambert-St Louis
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Highest demand for flights based on searches. 0% potential increase in price ($0 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Illinois to Lambert-St Louis.
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Price to beat on a one-way flight from Illinois to Lambert-St Louis.
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Find flight deals from Illinois to St. Louis

Cheapest flights from Illinois to St. Louis
Explore the most affordable flight options available from Illinois to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 16, 2025.

This Southwest deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/1512:40 pmMDW - STL
Nonstop1h 10mSouthwest
Wed 10/221:15 pmSTL - MDW
Nonstop1h 10mSouthwest
Deal found 9/15$97
This United Airlines deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/159:25 amORD - STL
Nonstop1h 24mUnited Airlines
Wed 10/225:00 amSTL - ORD
Nonstop1h 30mUnited Airlines
Deal found 9/15$97
This American Airlines deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/76:53 pmORD - STL
Nonstop1h 33mAmerican Airlines
Wed 10/228:42 amSTL - ORD
Nonstop1h 23mAmerican Airlines
Deal found 9/15$98
This Southwest deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/155:30 amMDW - STL
1 stop4h 45mSouthwest
Wed 10/155:05 pmSTL - MDW
Nonstop1h 05mSouthwest
Deal found 9/15$107
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/188:20 amMDW - STL
2 stops6h 10mSouthwest
Mon 10/207:35 amSTL - MDW
Nonstop1h 10mSouthwest
Deal found 9/14$112
This Southwest deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/71:30 pmORD - STL
1 stop7h 15mSouthwest
Wed 10/222:55 pmSTL - ORD
1 stop6h 35mSouthwest
Deal found 9/15$117
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/257:00 amORD - STL
1 stop5h 30mSouthwest
Sat 10/251:45 pmSTL - ORD
2 stops8h 15mSouthwest
Deal found 9/14$122
This eDestinos deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure eDestinos is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:20 amORD - STL
1 stop25h 46mFrontier
Thu 10/24:00 pmSTL - ORD
1 stop7h 39mFrontier
Deal found 9/14$125
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/247:40 amMDW - STL
Nonstop1h 10mSouthwest
Mon 10/275:40 amSTL - MDW
Nonstop1h 10mSouthwest
Deal found 9/14$134
This American Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/216:45 amORD - STL
Nonstop1h 24mAmerican Airlines
Fri 10/246:00 amSTL - ORD
Nonstop1h 23mAmerican Airlines
Deal found 9/14$134
This Priceline deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/296:20 amMDW - STL
1 stop8h 44mFrontier
Thu 10/24:00 pmSTL - MDW
1 stop7h 41mFrontier
Deal found 9/15$143
This Priceline deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/295:10 amORD - STL
1 stop9h 54mFrontier
Thu 10/24:00 pmSTL - ORD
1 stop7h 39mFrontier
Deal found 9/15$143

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 16, 2025.
Use the filters below to find and compare flights from Illinois to St. Louis that are best for you.

Fly from

Illinois

Fly to

St. Louis

Route

Depart

Return

Price

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Wed 11/5

11:25 am-12:35 pm

Nonstop1h 10m

Lambert-St Louis

Sat 11/8

5:45 pm-6:55 pm

Nonstop1h 10m

$97

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

Thu 11/6

6:44 am-8:09 am

Nonstop1h 25m

Lambert-St Louis

Sat 11/8

6:00 am-7:30 am

Nonstop1h 30m

$97

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

Wed 10/22

9:25 am-10:49 am

Nonstop1h 24m

Lambert-St Louis

Thu 10/23

5:00 am-6:30 am

Nonstop1h 30m

$97

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Tue 10/28

7:55 am-9:10 am

Nonstop1h 15m

Lambert-St Louis

Thu 10/30

6:30 pm-7:40 pm

Nonstop1h 10m

$97

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

Tue 10/21

10:34 pm-11:54 pm

Nonstop1h 20m

Lambert-St Louis

Mon 10/27

4:34 pm-6:02 pm

Nonstop1h 28m

$97

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

Thu 11/6

2:20 pm-3:46 pm

Nonstop1h 26m

Lambert-St Louis

Sat 11/8

5:24 pm-6:47 pm

Nonstop1h 23m

$97

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Wed 10/15

5:30 am-10:15 am

1 stop4h 45m

Lambert-St Louis

Wed 10/15

5:05 pm-6:10 pm

Nonstop1h 05m

$107

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Thu 10/9

7:40 am-8:50 am

Nonstop1h 10m

Lambert-St Louis

Mon 10/13

7:45 pm-11:55 pm

1 stop4h 10m

$107

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Sat 10/18

8:15 am-2:40 pm

1 stop6h 25m

Lambert-St Louis

Mon 10/20

7:35 am-8:45 am

Nonstop1h 10m

$107

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

Mon 11/3

10:05 am-4:05 pm

1 stop6h 00m

Lambert-St Louis

Mon 11/3

7:20 pm-8:30 pm

Nonstop1h 10m

$107

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/15

Showing 1-10 of 43 results
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Best time to book a flight from Illinois to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Illinois with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Illinois to St. Louis

What is the cheapest month to book a flight from Illinois to St. Louis?

Currently, August is the cheapest month in which you can book a flight from Illinois to St. Louis (average of $311). Flying from Illinois to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from IL to STL?

Find hourly flight availability from Illinois to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 16, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Illinois to St. Louis as you normally would.

Weekly flight availability from Illinois to St. Louis

Explore weekly flight availability from Illinois to St. Louis. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated September 16, 2025.

The most flights from USIL to STL are scheduled on a Monday (69 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (50 on average).

Related info for your journey

Find useful and relevant information for your journey from Illinois to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to St. Louis from Illinois?

    If you book a flight to St. Louis from Illinois, you will be flying to Lambert-St Louis, which is the city’s only airport. Lambert-St Louis (STL) is located 12.7 mi from the center of St. Louis.

  • How long is the flight from Illinois to St. Louis?

    Airlines like Southwest, American Airlines, and United Airlines fly from Illinois to St. Louis in about 1h 10m. The time it takes to get you to your destination is usually consistent. There are 251 mi between Illinois and St. Louis. Generally, flights for this route are nonstop.

  • What are the cheapest airlines to fly from Illinois to St. Louis one-way?

    The cheapest airline one-way is Southwest, with whom users have recently found tickets for as low as $49. However, be on the lookout for offers from United Airlines and American Airlines, as they are both options that can get you from Illinois to St. Louis for a low price.

  • What are the most popular routes from Illinois to St. Louis?

    When deciding which route to take from Illinois to St. Louis consider Chicago O'Hare Intl - Lambert-St Louis, Chicago Midway - Lambert-St Louis or Springfield Capital - Lambert-St Louis as they are the most popular.

  • What are the most reliable airlines from Illinois to St. Louis?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Illinois to St. Louis on time: SkyWest Airlines (81%), ANA (76%), Envoy Air (73%).

  • What are the cheapest flights from Illinois to St. Louis?

    Looking at all options, your cheapest flight can be booked for $48. While the most popular route (Chicago O'Hare Intl - Lambert-St Louis) can be booked for $97 on average, our data indicates $279 when flying from Illinois to St. Louis.

  • Can I find deals for flights from Illinois to St. Louis that include hotel bookings?

    Yes. In addition to deals on Illinois to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Illinois to St. Louis?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to St. Louis.

  • Can I find deals for business class flights from Illinois to St. Louis?

    Yes. Cheapflights offers flight deals from Illinois to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Illinois to St. Louis?

    Currently, August is the cheapest month in which you can book a flight from Illinois to St. Louis (average of $311). Flying from Illinois to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

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Top 4 airlines flying from Illinois to St. Louis

Discover the top 4 airlines that operate flights from Illinois to St. Louis. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$77Average$298FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$116Average$288FlexibilityNo cancel feeOn-time71%
Southern / MokuleleCheapest$118Average$221FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$152Average$320FlexibilityNo cancel feeOn-time69%

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