HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Illinois

$65+ 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 1/17. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
Jan 27 — Feb 31
Tue 1/27
Tue 2/3
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Illinois with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap 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 December 28, 2025.

This American Airlines deal was found by Cheapflights users on 12/28. 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.
Wed 12/315:00 amSTL - ORD
1 stop28h 21mAmerican Airlines
Thu 1/112:10 pmORD - STL
Nonstop1h 26mAmerican Airlines
Deal found 12/28$286
This American Airlines deal was found by Cheapflights users on 12/26. 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.
Sat 12/272:08 pmSTL - ORD
Nonstop1h 26mAmerican Airlines
Sat 12/276:38 pmORD - STL
1 stop18h 36mAmerican Airlines
Deal found 12/26$401
This Frontier deal was found by Cheapflights users on 12/25. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/2910:40 amSTL - MDW
1 stop11h 18mFrontier
Wed 12/313:10 pmMDW - STL
1 stop7h 23mFrontier
Deal found 12/25$442
This Frontier deal was found by Cheapflights users on 12/26. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/3010:48 amSTL - ORD
1 stop11h 36mFrontier
Thu 1/111:28 amORD - STL
1 stop11h 05mFrontier
Deal found 12/26$442
This Frontier deal was found by Cheapflights users on 12/25. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/2910:40 amSTL - MDW
1 stop11h 18mFrontier
Fri 1/23:10 pmMDW - STL
1 stop7h 23mFrontier
Deal found 12/25$462
This American Airlines deal was found by Cheapflights users on 12/26. 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.
Sat 12/279:08 amSTL - ORD
Nonstop1h 27mAmerican Airlines
Tue 1/201:25 pmORD - STL
Nonstop1h 25mAmerican Airlines
Deal found 12/26$468
This Southwest deal was found by Cheapflights users on 12/27. 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.
Mon 12/296:45 amSTL - ORD
1 stop5h 30mSouthwest
Sat 1/311:45 pmORD - STL
1 stop6h 25mSouthwest
Deal found 12/27$477
This American Airlines deal was found by Cheapflights users on 12/27. 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.
Mon 12/292:04 pmSTL - ORD
1 stop5h 18mAmerican Airlines
Sat 1/314:42 pmORD - STL
Nonstop1h 31mAmerican Airlines
Deal found 12/27$487
This Delta deal was found by Cheapflights users on 12/26. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/277:02 pmSTL - ORD
1 stop5h 00mDelta
Tue 1/205:59 pmORD - STL
1 stop5h 38mDelta
Deal found 12/26$488
This American Airlines deal was found by Cheapflights users on 12/26. 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.
Fri 12/266:35 pmSTL - ORD
1 stop18h 05mAmerican Airlines
Sat 12/272:57 pmORD - STL
Nonstop1h 26mAmerican Airlines
Deal found 12/26$494
This American Airlines deal was found by Cheapflights users on 12/27. 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 12/306:35 pmSTL - ORD
1 stop14h 46mAmerican Airlines
Wed 12/3112:10 pmORD - STL
Nonstop1h 26mAmerican Airlines
Deal found 12/27$495
This American Airlines deal was found by Cheapflights users on 12/26. 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.
Mon 12/298:01 pmSTL - ORD
Nonstop1h 29mAmerican Airlines
Thu 1/12:57 pmORD - STL
Nonstop1h 26mAmerican Airlines
Deal found 12/26$499

Find 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 December 28, 2025.

Most accurate provider

Justfly.com
3 stars

Most trusted provider

Justfly.com
3 stars

Round-trip from

$139
(Kiwi.com)

One-way from

$65
(Kiwi.com)

Popular in

December

Cheapest in

August

Average price

$333

Good round-trip deal

$317 or less

Good one-way deal

$224 or less
Provider with most accurate pricing for Lambert-St Louis-Chicago (CHI) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Chicago (CHI) flights.
Search Deals
From Lambert-St Louis to Illinois
Search Deals
One-way flight from Lambert-St Louis to Illinois
Search Deals
Highest demand for flights based on searches. 9% potential increase in price ($27 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a round-trip flight from Lambert-St Louis to Illinois.
Search Deals
Price to beat on a one-way flight from Lambert-St Louis to Illinois.
Search Deals

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 December 28, 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. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Sat 1/17

5:50 pm-7:00 pm

Nonstop1h 10m

Chicago Midway

Mon 1/19

8:15 am-9:35 am

Nonstop1h 20m

$157

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Sat 1/24

10:25 am-11:35 am

Nonstop1h 10m

Chicago Midway

Mon 1/26

9:55 am-11:15 am

Nonstop1h 20m

$157

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Wed 1/21

6:00 am-7:27 am

Nonstop1h 27m

Chicago O'Hare Intl

Sat 1/31

4:42 pm-6:13 pm

Nonstop1h 31m

$162

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Sat 1/24

8:05 am-9:40 am

Nonstop1h 35m

Chicago O'Hare Intl

Sat 1/31

2:35 pm-4:03 pm

Nonstop1h 28m

$171

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Thu 2/5

4:30 pm-5:40 pm

Nonstop1h 10m

Chicago Midway

Mon 2/9

8:15 am-9:35 am

Nonstop1h 20m

$171

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Wed 2/25

7:10 am-11:59 am

1 stop4h 49m

Chicago Midway

Wed 2/25

6:40 pm-11:36 pm

1 stop4h 56m

$173

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Tue 2/24

6:00 am-11:59 am

1 stop5h 59m

Chicago Midway

Tue 3/3

6:00 am-11:02 am

1 stop5h 02m

$173

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Tue 2/17

6:10 am-12:46 pm

2 stops6h 36m

Chicago Midway

Tue 2/24

6:00 am-11:02 am

1 stop5h 02m

$178

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Wed 2/18

6:10 am-1:20 pm

2 stops7h 10m

Chicago O'Hare Intl

Wed 2/25

2:05 pm-8:43 pm

1 stop6h 38m

$178

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Sat 1/24

3:46 pm-10:57 am

1 stop19h 11m

Chicago O'Hare Intl

Sat 1/31

12:44 pm-11:33 pm

1 stop10h 49m

$180

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/26

Showing 1-10 of 46 results
1
2
3
...
5

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, November is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $77). Flying from St. Louis to Illinois in June is currently the most expensive (average of $172). 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 December 28, 2025.

When flying from St. Louis to Illinois, the time of day you fly usually plays a role in the price. Save by searching for a flight in the morning, which can drop the price by up to 35% versus a flight at noon.

What is the cheapest day to fly from St. Louis to Illinois?

Use this chart to determine the cheapest time to fly round-trip from St. Louis to Illinois. Price data was last updated on December 27, 2025.

Travelers seeking maximum savings on their St. Louis to Illinois flight should consider departing on Tuesday at noon when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

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 December 28, 2025.

The most flights from STL to USIL are scheduled on a Friday (58 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (25 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 December 28, 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
4,256 reviews

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
Southwest
8.0
Very good
4,256 reviews
Southwest
8.0
Very good
4,256 reviews

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
United Airlines
7.4
Good
9,117 reviews
Southwest
8.0
Very good
4,256 reviews

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
American Airlines
7.2
Good
11,072 reviews
Southwest
8.0
Very good
4,256 reviews

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
Southern / Mokulele
6.8
Okay
30 reviews
Southwest
8.0
Very good
4,256 reviews

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

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 1h 10m. Southwest provides one of the quickest options available for as low as $157. St. Louis and Illinois are separated by a distance of 251 mi. All flights are typically nonstop.

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

    For one-way options, check prices for Southern / Mokulele. According to our data, you can fly for as low as $33. Users have also found prices from $45 and $48 on Southwest and American Airlines, 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 - Decatur Arpt 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: American Airlines (73%), ANA (70%), Republic Airways (70%).

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

    The cheapest flight price from St. Louis to Illinois is $125. On average you can expect to pay $1,144. The most popular route, (Lambert-St Louis - Chicago O'Hare Intl), can usually be booked for $153.

  • 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, November is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $77). Flying from St. Louis to Illinois in June is currently the most expensive (average of $172). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for St. Louis to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
St. Louis to Las Vegas flights
St. Louis to Orlando flights
Kansas City to Las Vegas flights
Kansas City to Orlando flights
Kansas City to Sky Harbor Intl flights
Kansas City to Denver flights
St. Louis to Miami flights
St. Louis to Newark flights
St. Louis to LaGuardia flights
St. Louis to Denver flights
St. Louis to Sky Harbor Intl flights
Kansas City to LaGuardia flights
St. Louis to Seattle flights
Kansas City to John F Kennedy Intl flights
St. Louis to Hobby flights
Kansas City to Los Angeles flights
Kansas City to Miami flights
St. Louis to Los Angeles flights
Kansas City to O'Hare Intl flights
Kansas City to Hobby flights
Kansas City to Newark flights
St. Louis to Fort Lauderdale flights
Kansas City to Seattle flights
St. Louis to George Bush Intcntl flights
Kansas City to Fort Lauderdale flights
Kansas City to Atlanta flights
St. Louis to Atlanta flights
St. Louis to Tampa flights
Kansas City to Dallas/Fort Worth flights
St. Louis to John F Kennedy Intl flights
St. Louis to Dallas/Fort Worth flights
Kansas City to George Bush Intcntl flights
St. Louis to Honolulu flights
St. Louis to Salt Lake City flights
Kansas City to Tampa flights
Kansas City to Boston flights
St. Louis to San Francisco flights
St. Louis to New Orleans flights
St. Louis to Boston flights
St. Louis to O'Hare Intl flights
Kansas City to Honolulu flights
St. Louis to Baltimore flights
Springfield to Seattle flights
St. Louis to San Diego flights
St. Louis to Fort Myers flights
St. Louis to Kailua-Kona flights
St. Louis to Dulles Intl flights
Kansas City to San Francisco flights
St. Louis to Philadelphia flights
Kansas City to New Orleans flights

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 December 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$97Average$303FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$106Average$281FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$114Average$308FlexibilityNo cancel feeOn-time69%
Southern / MokuleleCheapest$140Average$223FlexibilityNo cancel feeOn-timeN/A

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.