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$39+ Cheap flights from St. Louis (STL) to Illinois

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 10/25. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
ago. 25 — sep. 11
lun. 8/25
lun. 9/1
1 adult, Economy
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Cheap flight deals from St. Louis to Illinois

Keep the following information in mind while searching for St. Louis to Illinois flight deals. Data was last updated agosto 20, 2025.

Round-trip from

$72
(Trip.com)

One-way from

$39
(Southwest)

Popular in

April

Cheapest in

August

Average price

$206

Good round-trip deal

$78 or less

Good one-way deal

$59 or less
From Lambert-St Louis to Illinois
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One-way flight from Lambert-St Louis to Illinois
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Highest demand for flights based on searches. 9% potential increase in price ($24 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($4 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Price to beat on a round-trip flight from Lambert-St Louis to Illinois.
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Price to beat on a one-way flight from Lambert-St Louis to Illinois.
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Find flight deals from St. Louis to Illinois

Cheapest flights from St. Louis to Illinois
Explore the most affordable flight options available from St. Louis to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on agosto 20, 2025.

This Trip.com deal was found by Cheapflights users on 8/19. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/121:00 pmSTL - UIN
Nonstop0h 51mSouthern / Mokulele
lun. 9/157:50 amUIN - STL
Nonstop0h 50mSouthern / Mokulele
Deal found 8/19$72
This Southwest deal was found by Cheapflights users on 8/18. 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.
jue. 9/116:50 pmSTL - MDW
1 stop4h 00mSouthwest
lun. 9/156:30 amMDW - STL
Nonstop1h 10mSouthwest
Deal found 8/18$87
This American Airlines deal was found by Cheapflights users on 8/18. 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.
mié. 9/176:10 amSTL - ORD
Nonstop1h 20mAmerican Airlines
mié. 9/247:10 pmORD - STL
Nonstop1h 22mAmerican Airlines
Deal found 8/18$91
This American Airlines deal was found by Cheapflights users on 8/19. 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.
mié. 9/106:10 amSTL - ORD
Nonstop1h 20mAmerican Airlines
mié. 9/108:31 pmORD - STL
Nonstop1h 22mAmerican Airlines
Deal found 8/19$92
This Southwest deal was found by Cheapflights users on 8/18. 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.
mar. 9/162:30 pmSTL - MDW
1 stop4h 35mSouthwest
mié. 10/156:15 amMDW - STL
1 stop5h 30mSouthwest
Deal found 8/18$97
This Southwest deal was found by Cheapflights users on 8/20. 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.
mar. 9/98:10 amSTL - ORD
1 stop8h 35mSouthwest
mié. 9/101:50 pmORD - STL
1 stop8h 05mSouthwest
Deal found 8/20$97
This American Airlines deal was found by Cheapflights users on 8/17. 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.
sáb. 9/137:23 amSTL - ORD
Nonstop1h 22mAmerican Airlines
mar. 9/167:10 pmORD - STL
Nonstop1h 22mAmerican Airlines
Deal found 8/17$104
This Southwest deal was found by Cheapflights users on 8/18. 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.
mié. 10/158:15 amSTL - MDW
1 stop4h 40mSouthwest
jue. 10/169:40 amMDW - STL
Nonstop1h 15mSouthwest
Deal found 8/18$107
This American Airlines deal was found by Cheapflights users on 8/18. 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.
mié. 10/158:42 amSTL - ORD
Nonstop1h 23mAmerican Airlines
jue. 10/166:53 pmORD - STL
Nonstop1h 33mAmerican Airlines
Deal found 8/18$107
This Southwest deal was found by Cheapflights users on 8/19. 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.
mar. 9/98:50 pmSTL - MDW
Nonstop1h 05mSouthwest
vie. 9/127:30 amMDW - STL
Nonstop1h 10mSouthwest
Deal found 8/19$114
This United Airlines deal was found by Cheapflights users on 8/19. 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.
vie. 9/197:04 pmSTL - ORD
Nonstop1h 32mUnited Airlines
mar. 9/232:20 pmORD - STL
Nonstop1h 24mUnited Airlines
Deal found 8/19$114
This United Airlines deal was found by Cheapflights users on 8/17. 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.
lun. 9/153:20 pmSTL - ORD
Nonstop1h 25mUnited Airlines
lun. 9/224:55 pmORD - STL
Nonstop1h 28mUnited Airlines
Deal found 8/17$117

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to Illinois 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 agosto 20, 2025.
Use the filters below to find and compare flights from St. Louis to Illinois that are best for you.

Fly from

St. Louis

Fly to

Illinois

Route

Depart

Return

Price

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

vie. 9/12

1:00 pm-1:51 pm

Nonstop0h 51m

Quincy Regional

lun. 9/15

7:50 am-8:40 am

Nonstop0h 50m

$72

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

jue. 10/16

8:40 pm-9:31 pm

Nonstop0h 51m

Quincy Regional

vie. 10/24

7:50 am-8:40 am

Nonstop0h 50m

$78

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

jue. 9/11

1:00 pm-1:51 pm

Nonstop0h 51m

Quincy Regional

vie. 9/12

7:50 am-8:40 am

Nonstop0h 50m

$78

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

jue. 10/16

8:40 pm-9:31 pm

Nonstop0h 51m

Quincy Regional

sáb. 10/25

7:50 am-8:40 am

Nonstop0h 50m

$78

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mar. 9/9

9:45 am-2:20 pm

1 stop4h 35m

Chicago Midway

mié. 9/10

9:00 am-10:15 am

Nonstop1h 15m

$87

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

jue. 9/11

6:50 pm-10:50 pm

1 stop4h 00m

Chicago Midway

lun. 9/15

6:30 am-7:40 am

Nonstop1h 10m

$87

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mar. 9/16

8:50 pm-9:55 pm

Nonstop1h 05m

Chicago Midway

mar. 9/23

3:25 pm-8:05 pm

1 stop4h 40m

$87

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mié. 10/15

2:45 pm-7:40 pm

1 stop4h 55m

Chicago Midway

jue. 10/16

7:40 am-8:50 am

Nonstop1h 10m

$87

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mié. 9/17

2:05 pm-3:10 pm

Nonstop1h 05m

Chicago Midway

mié. 9/24

8:30 am-1:40 pm

1 stop5h 10m

$87

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mié. 10/1

8:15 am-1:50 pm

1 stop5h 35m

Chicago Midway

mié. 10/8

5:45 am-6:55 am

Nonstop1h 10m

$87

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/20

Showing 1-10 of 51 results
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Best time to book a flight from St. Louis to Illinois

Have a flexible travel schedule? Discover the best time to fly to Illinois from St. Louis 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 St. Louis to Illinois

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

Currently, August is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $245). Flying from St. Louis to Illinois in March is currently the most expensive (average of $321). 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 STL to IL?

Find hourly flight availability from St. Louis to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated agosto 20, 2025.

When flying from St. Louis to Illinois, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from St. Louis to Illinois

Explore weekly flight availability from St. Louis to Illinois. 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 agosto 20, 2025.

The most flights from STL to USIL are scheduled on a Monday (65 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (43 on average).

Reviews of airlines servicing Illinois

Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated agosto 20, 2025.
See what other customers who have flown with Southwest, United Airlines, and American Airlines from St. Louis to Illinois have to say. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,246 reviews

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,928 reviews
Southwest
8.0
Very good
4,246 reviews

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,246 reviews

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Illinois. 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 from for flights from St. Louis to Illinois?

    Located just 12.7 mi from the city center, Lambert-St Louis (STL) is the airport most travelers will use when flying to Illinois from St. Louis.

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

    A quick flight from St. Louis to Illinois can take about 51m. Southern / Mokulele provides one of the quickest options available for as low as $72. St. Louis and Illinois are separated by a distance of 93 mi. This flight may include one or multiple stops.

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

    For one-way options, check prices for United Airlines. According to our data, you can fly for as low as $39. Users have also found prices from $49 and $57 on Southwest and Southern / Mokulele, respectively.

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

    Most travelers choose Lambert-St Louis - Chicago O'Hare Intl, Lambert-St Louis - Chicago Midway or Lambert-St Louis - Quincy Regional when deciding on the best route from St. Louis to Illinois.

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

    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 St. Louis to Illinois on time: Avianca (75%), Royal Jordanian (75%), Japan Airlines (74%).

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

    The cheapest flight price from St. Louis to Illinois is $112. On average you can expect to pay $1,127. The most popular route, (Lambert-St Louis - Chicago O'Hare Intl), can usually be booked for $77.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from St. Louis to Illinois 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 St. Louis to Illinois?

    Currently, August is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $245). Flying from St. Louis to Illinois in March is currently the most expensive (average of $321). 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

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Alternative routes for St. Louis to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
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Top 4 airlines flying from St. Louis to Illinois

Discover the top 4 airlines that operate flights from St. Louis to Illinois. 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 agosto 20, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$115Average$272FlexibilityNo cancel feeOn-time71%
Southern / MokuleleCheapest$125Average$204FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$146Average$288FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$151Average$316FlexibilityNo cancel feeOn-time69%

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