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$37+ 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 7/4. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
jun. 17 — jun. 241
mar. 6/17
mar. 6/24
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 junio 12, 2025.

Round-trip from

$78
(Orbitz)

One-way from

$37
(Trip.com)

Popular in

June

Cheapest in

August

Average price

$323

Good round-trip deal

$78 or less

Good one-way deal

$106 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. 6% potential increase in price ($15 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in June 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 junio 12, 2025.

This Orbitz deal was found by Cheapflights users on 6/11. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 7/178:40 pmSTL - UIN
Nonstop1h 00mSouthern / Mokulele
mié. 7/2311:10 amUIN - STL
Nonstop1h 00mSouthern / Mokulele
Deal found 6/11$78
This Southwest deal was found by Cheapflights users on 6/11. 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. 8/611:35 amSTL - MDW
Nonstop1h 05mSouthwest
lun. 8/186:05 pmMDW - STL
Nonstop1h 15mSouthwest
Deal found 6/11$97
This American Airlines deal was found by Cheapflights users on 6/11. 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. 8/218:50 amSTL - ORD
Nonstop1h 31mAmerican Airlines
jue. 9/410:34 pmORD - STL
Nonstop1h 14mAmerican Airlines
Deal found 6/11$97
This Southwest deal was found by Cheapflights users on 6/10. 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. 8/56:25 amSTL - ORD
1 stop6h 20mSouthwest
mié. 8/61:50 pmORD - STL
1 stop8h 05mSouthwest
Deal found 6/10$117
This Trip.com deal was found by Cheapflights users on 6/12. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 8/75:00 amSTL - ORD
Nonstop1h 30mUnited Airlines
lun. 8/119:20 pmORD - STL
Nonstop1h 25mUnited Airlines
Deal found 6/12$155
This Trip.com deal was found by Cheapflights users on 6/10. 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. 7/251:00 pmSTL - ORD
1 stop3h 32mSouthern / Mokulele
dom. 7/278:15 amORD - STL
1 stop3h 55mSouthern / Mokulele
Deal found 6/10$166
This Delta deal was found by Cheapflights users on 6/10. 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.
sáb. 11/86:30 amSTL - MDW
1 stop6h 39mDelta
mar. 11/116:00 amMDW - STL
1 stop4h 40mDelta
Deal found 6/10$177
This Delta deal was found by Cheapflights users on 6/10. 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.
sáb. 11/84:45 pmSTL - ORD
1 stop5h 07mDelta
mar. 11/111:16 pmORD - STL
1 stop4h 46mDelta
Deal found 6/10$177
This Frontier deal was found by Cheapflights users on 6/10. 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.
sáb. 7/262:52 pmSTL - MDW
1 stop7h 43mFrontier
dom. 7/276:20 amMDW - STL
1 stop7h 14mFrontier
Deal found 6/10$221
This FlightHub deal was found by Cheapflights users on 6/11. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 7/911:24 amSTL - ORD
1 stop9h 04mMultiple Airlines
mié. 7/168:15 amORD - STL
1 stop3h 55mMultiple Airlines
Deal found 6/11$225
This Mytrip deal was found by Cheapflights users on 6/9. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 6/307:13 pmSTL - ORD
2 stops14h 25mSpirit Airlines
mié. 7/21:43 pmORD - STL
2 stops27h 21mSpirit Airlines
Deal found 6/9$234
This United Airlines deal was found by Cheapflights users on 6/11. 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.
jue. 6/265:00 amSTL - DEC
1 stop3h 48mUnited Airlines
lun. 6/306:55 pmDEC - STL
1 stop3h 50mUnited Airlines
Deal found 6/11$350

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 junio 12, 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. 7/17

8:40 pm-9:40 pm

Nonstop1h 00m

Quincy Regional

mié. 7/23

11:10 am-12:10 pm

Nonstop1h 00m

$78

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

jue. 8/7

6:00 pm-11:50 pm

1 stop5h 50m

Chicago Midway

lun. 8/11

7:30 am-8:40 am

Nonstop1h 10m

$87

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

jue. 8/21

8:50 am-10:21 am

Nonstop1h 31m

Chicago O'Hare Intl

jue. 9/4

10:34 pm-11:48 pm

Nonstop1h 14m

$97

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

mar. 8/5

6:25 am-12:45 pm

1 stop6h 20m

Chicago O'Hare Intl

mié. 8/6

1:50 pm-9:55 pm

1 stop8h 05m

$117

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

jue. 8/7

5:00 am-6:30 am

Nonstop1h 30m

Chicago O'Hare Intl

lun. 8/11

9:20 pm-10:45 pm

Nonstop1h 25m

$155

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

vie. 7/25

1:00 pm-4:32 pm

1 stop3h 32m

Chicago O'Hare Intl

dom. 7/27

8:15 am-12:10 pm

1 stop3h 55m

$166

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

sáb. 11/8

6:30 am-1:09 pm

1 stop6h 39m

Chicago Midway

mar. 11/11

6:00 am-10:40 am

1 stop4h 40m

$177

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

sáb. 11/8

4:45 pm-9:52 pm

1 stop5h 07m

Chicago O'Hare Intl

mar. 11/11

1:16 pm-6:02 pm

1 stop4h 46m

$177

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

sáb. 7/26

2:52 pm-10:35 pm

1 stop7h 43m

Chicago Midway

dom. 7/27

6:20 am-1:34 pm

1 stop7h 14m

$221

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

mié. 7/9

11:24 am-8:28 pm

1 stop9h 04m

Chicago O'Hare Intl

mié. 7/16

8:15 am-12:10 pm

1 stop3h 55m

$225

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 27 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 junio 12, 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 junio 12, 2025.

The most flights from STL to USIL are scheduled on a Monday (76 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (27 on average).

Rainfall in Illinois by month

Plan your trip to Illinois by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.

Temperature in Illinois by month

Plan your trip to Illinois by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Illinois, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).

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 junio 12, 2025.
Peruse reviews from past customers who have flown with Southwest, Delta and United Airlines from St. Louis to Illinois to help guide your decision. 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
4,287 reviews

Crew

8.6

Overall

8.0

Boarding

8.2

Comfort

8.0

Food

7.1

Entertainment

7.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Southwest
8.0
Very good
4,287 reviews
Southwest
8.0
Very good
4,287 reviews

Crew

8.6

Overall

8.0

Boarding

8.2

Comfort

8.0

Food

7.1

Entertainment

7.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Delta
8.0
Very good
7,946 reviews
Southwest
8.0
Very good
4,287 reviews

Crew

8.6

Overall

8.0

Boarding

8.2

Comfort

8.0

Food

7.1

Entertainment

7.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
United Airlines
7.4
Good
8,790 reviews
Southwest
8.0
Very good
4,287 reviews

Crew

8.6

Overall

8.0

Boarding

8.2

Comfort

8.0

Food

7.1

Entertainment

7.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,287 reviews

Crew

8.6

Overall

8.0

Boarding

8.2

Comfort

8.0

Food

7.1

Entertainment

7.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.

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.

  • 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 $37. Users have also found prices from $59 and $62 on Southwest and United 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 - 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: SkyWest Airlines (90%), Finnair (89%), Copa Airlines (89%).

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

    The cheapest flight price from St. Louis to Illinois is $120. On average you can expect to pay $2,443. 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 junio 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$115Average$268FlexibilityNo cancel feeOn-time71%
Southern / MokuleleCheapest$118Average$182FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$126Average$306FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$168Average$284FlexibilityNo cancel feeOn-time63%

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