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$49+ 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 12/11. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
oct. 15 — oct. 221
mié. 10/15
mié. 10/22
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 septiembre 15, 2025.

Round-trip from

$68
(Orbitz)

One-way from

$49
(Southwest)

Popular in

April

Cheapest in

August

Average price

$268

Good round-trip deal

$78 or less

Good one-way deal

$113 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. 7% potential increase in price ($22 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 September 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 septiembre 15, 2025.

This Trip.com deal was found by Cheapflights users on 9/13. 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.
jue. 10/98:40 pmSTL - UIN
Nonstop0h 51mSouthern / Mokulele
jue. 10/163:45 pmUIN - STL
Nonstop0h 50mSouthern / Mokulele
Deal found 9/13$61
This Southern / Mokulele deal was found by Cheapflights users on 9/13. 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 Southern / Mokulele is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 9/239:20 amSTL - UIN
Nonstop0h 51mSouthern / Mokulele
sáb. 9/277:50 amUIN - STL
Nonstop0h 50mSouthern / Mokulele
Deal found 9/13$68
This Southern / Mokulele 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 Southern / Mokulele is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 10/38:40 pmSTL - UIN
Nonstop0h 51mSouthern / Mokulele
sáb. 10/47:50 amUIN - STL
Nonstop0h 50mSouthern / Mokulele
Deal found 9/14$84
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.
jue. 10/235:40 amSTL - MDW
Nonstop1h 10mSouthwest
lun. 10/277:40 amMDW - STL
Nonstop1h 10mSouthwest
Deal found 9/15$97
This United Airlines deal was found by Cheapflights users on 9/13. 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.
sáb. 10/115:28 pmSTL - ORD
Nonstop1h 25mUnited Airlines
sáb. 10/189:25 amORD - STL
Nonstop1h 24mUnited Airlines
Deal found 9/13$97
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.
jue. 10/237:16 amSTL - ORD
Nonstop1h 27mAmerican Airlines
lun. 10/2710:34 pmORD - STL
Nonstop1h 20mAmerican Airlines
Deal found 9/14$98
This American Airlines deal was found by Cheapflights users on 9/12. 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. 10/45:25 pmSTL - ORD
Nonstop1h 33mAmerican Airlines
sáb. 10/116:53 pmORD - STL
Nonstop1h 33mAmerican Airlines
Deal found 9/12$99
This Southwest deal was found by Cheapflights users on 9/13. 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. 11/197:00 amSTL - MDW
Nonstop1h 10mSouthwest
lun. 11/249:30 amMDW - STL
2 stops4h 45mSouthwest
Deal found 9/13$112
This American Airlines deal was found by Cheapflights users on 9/13. 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. 11/18:00 pmSTL - ORD
Nonstop1h 26mAmerican Airlines
dom. 11/96:44 amORD - STL
Nonstop1h 25mAmerican Airlines
Deal found 9/13$115
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.
lun. 10/205:55 amSTL - ORD
1 stop6h 50mSouthwest
mar. 10/211:30 pmORD - STL
1 stop5h 35mSouthwest
Deal found 9/15$117
This Southwest deal was found by Cheapflights users on 9/13. 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. 10/141:30 pmSTL - ORD
1 stop9h 35mSouthwest
mié. 10/227:30 amORD - STL
1 stop7h 15mSouthwest
Deal found 9/13$122
This United Airlines deal was found by Cheapflights users on 9/12. 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. 10/1712:25 pmSTL - ORD
Nonstop1h 25mUnited Airlines
dom. 10/199:25 amORD - STL
Nonstop1h 24mUnited Airlines
Deal found 9/12$133

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 septiembre 15, 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

jue. 10/9

8:40 pm-9:31 pm

Nonstop0h 51m

Quincy Regional

jue. 10/16

3:45 pm-4:35 pm

Nonstop0h 50m

$68

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

vie. 10/3

8:40 pm-9:31 pm

Nonstop0h 51m

Quincy Regional

sáb. 10/4

7:50 am-8:40 am

Nonstop0h 50m

$84

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

jue. 10/23

5:40 am-6:50 am

Nonstop1h 10m

Chicago Midway

lun. 10/27

7:40 am-8:50 am

Nonstop1h 10m

$97

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

sáb. 11/8

7:58 pm-9:29 pm

Nonstop1h 31m

Chicago O'Hare Intl

mar. 11/11

3:23 pm-4:47 pm

Nonstop1h 24m

$97

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

mié. 11/19

7:00 am-8:10 am

Nonstop1h 10m

Chicago Midway

lun. 11/24

6:45 am-8:00 am

Nonstop1h 15m

$97

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

lun. 10/20

5:40 am-6:50 am

Nonstop1h 10m

Chicago Midway

lun. 10/20

6:00 pm-9:30 pm

1 stop3h 30m

$107

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

vie. 11/14

6:43 pm-8:13 pm

Nonstop1h 30m

Chicago O'Hare Intl

sáb. 11/15

2:20 pm-3:46 pm

Nonstop1h 26m

$115

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

sáb. 11/15

6:00 am-7:30 am

Nonstop1h 30m

Chicago O'Hare Intl

dom. 11/23

2:50 pm-4:16 pm

Nonstop1h 26m

$115

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

vie. 10/17

12:25 pm-1:50 pm

Nonstop1h 25m

Chicago O'Hare Intl

dom. 10/19

9:25 am-10:49 am

Nonstop1h 24m

$133

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

lun. 10/20

5:28 pm-6:53 pm

Nonstop1h 25m

Chicago O'Hare Intl

vie. 10/24

9:25 am-10:49 am

Nonstop1h 24m

$134

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/13

Showing 1-10 of 40 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 septiembre 15, 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 septiembre 15, 2025.

The most flights from STL to USIL are scheduled on a Monday (73 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (55 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 septiembre 15, 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
4,242 reviews

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
United Airlines
7.4
Good
8,929 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

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 $68. St. Louis and Illinois are separated by a distance of 93 mi. All flights are typically nonstop.

  • 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: Qatar Airways (80%), Avianca (80%), Japan Airlines (78%).

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

    The cheapest flight price from St. Louis to Illinois is $99. On average you can expect to pay $916. The most popular route, (Lambert-St Louis - Chicago O'Hare Intl), can usually be booked for $97.

  • 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 septiembre 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$117Average$277FlexibilityNo cancel feeOn-time71%
Southern / MokuleleCheapest$140Average$217FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$143Average$314FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$151Average$294FlexibilityNo cancel feeOn-time63%

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