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$35+ 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 2/28. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
Jan 27 — Feb 31
Mon 1/27
Mon 2/3
1 adult, Economy
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Cheap flight deals from St. Louis to Illinois

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Illinois (USIL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated January 22, 2025.

Round-trip from

$77
(Trip.com)

One-way from

$35
(Booking.com)

Good round-trip deal

$196 or less

Good one-way deal

$121 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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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 January 22, 2025.

This Trip.com deal was found by Cheapflights users on 1/22. 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.
Mon 2/109:20 amSTL - UIN
Nonstop1h 00mSouthern / Mokulele
Sun 2/163:45 pmUIN - STL
Nonstop1h 00mSouthern / Mokulele
Deal found 1/22$77
This Mytrip deal was found by Cheapflights users on 1/21. 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.
Fri 3/712:15 pmSTL - ORD
1 stop3h 35mSouthern / Mokulele
Fri 3/148:25 amORD - STL
1 stop11h 45mSouthern / Mokulele
Deal found 1/21$125
This Mytrip deal was found by Cheapflights users on 1/21. 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.
Fri 2/2812:15 pmSTL - ORD
1 stop3h 35mMultiple Airlines
Mon 3/34:58 pmORD - STL
1 stop6h 45mMultiple Airlines
Deal found 1/21$126
This Southwest deal was found by Cheapflights users on 1/21. 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.
Thu 2/139:15 pmSTL - MDW
Nonstop1h 15mSouthwest
Mon 2/175:25 amMDW - STL
Nonstop1h 20mSouthwest
Deal found 1/21$137
This United Airlines deal was found by Cheapflights users on 1/21. 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.
Thu 2/203:32 pmSTL - ORD
Nonstop1h 22mUnited Airlines
Wed 2/262:20 pmORD - STL
Nonstop1h 20mUnited Airlines
Deal found 1/21$137
This American Airlines deal was found by Cheapflights users on 1/22. 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.
Thu 2/135:45 amSTL - ORD
Nonstop1h 24mAmerican Airlines
Mon 2/178:45 pmORD - STL
Nonstop1h 18mAmerican Airlines
Deal found 1/22$138
This Frontier deal was found by Cheapflights users on 1/22. 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.
Thu 2/68:31 pmSTL - MDW
1 stop15h 13mFrontier
Mon 2/1011:33 amMDW - STL
1 stop12h 08mFrontier
Deal found 1/22$150
This KAYAK deal was found by Cheapflights users on 1/22. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/107:10 pmSTL - ORD
1 stop4h 46mDelta
Tue 3/115:45 amORD - STL
1 stop6h 15mDelta
Deal found 1/22$174
This Delta deal was found by Cheapflights users on 1/21. 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.
Wed 2/126:00 amSTL - MDW
1 stop4h 12mDelta
Thu 2/136:00 amMDW - STL
1 stop5h 46mDelta
Deal found 1/21$177
This Southwest deal was found by Cheapflights users on 1/21. 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 2/111:15 pmSTL - ORD
1 stop8h 15mSouthwest
Wed 2/126:15 amORD - STL
2 stops10h 40mSouthwest
Deal found 1/21$177
This United Airlines deal was found by Cheapflights users on 1/22. 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.
Thu 2/69:44 amSTL - DEC
1 stop4h 53mUnited Airlines
Mon 2/1010:00 amDEC - STL
1 stop11h 45mUnited Airlines
Deal found 1/22$546

Find flights from St. Louis to Illinois within your budget

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 January 22, 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisQuincy

STL - UIN

STLUIN

Lambert-St Louis

Mon 2/10

9:20 am-10:20 am

Nonstop1h 00m

Quincy Regional

Sun 2/16

3:45 pm-4:45 pm

Nonstop1h 00m

$77

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Sun 3/16

12:15 pm-3:50 pm

1 stop3h 35m

Chicago O'Hare Intl

Fri 3/28

8:25 am-8:10 pm

1 stop11h 45m

$130

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Thu 2/13

6:00 am-7:10 am

Nonstop1h 10m

Chicago Midway

Mon 2/17

10:35 pm-11:50 pm

Nonstop1h 15m

$137

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Thu 2/20

3:32 pm-4:54 pm

Nonstop1h 22m

Chicago O'Hare Intl

Wed 2/26

2:20 pm-3:40 pm

Nonstop1h 20m

$137

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Thu 2/13

5:45 am-7:09 am

Nonstop1h 24m

Chicago O'Hare Intl

Mon 2/17

8:45 pm-10:03 pm

Nonstop1h 18m

$138

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Thu 2/6

8:31 pm-11:44 am

1 stop15h 13m

Chicago Midway

Mon 2/10

11:33 am-11:41 pm

1 stop12h 08m

$150

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Sat 2/15

8:52 pm-5:05 am

1 stop8h 13m

Chicago O'Hare Intl

Mon 2/17

8:25 am-8:10 pm

1 stop11h 45m

$153

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Mon 3/10

7:10 pm-11:56 pm

1 stop4h 46m

Chicago O'Hare Intl

Tue 3/11

5:45 am-12:00 pm

1 stop6h 15m

$174

St. LouisChicago

STL - MDW

STLMDW

Lambert-St Louis

Wed 2/12

6:00 am-10:12 am

1 stop4h 12m

Chicago Midway

Thu 2/13

6:00 am-11:46 am

1 stop5h 46m

$177

St. LouisChicago

STL - ORD

STLORD

Lambert-St Louis

Fri 2/28

5:20 am-2:00 pm

2 stops8h 40m

Chicago O'Hare Intl

Fri 2/28

4:20 pm-12:05 am

1 stop7h 45m

$246

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/22

Showing 1-10 of 24 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.

Travel insights for flights from St. Louis to Illinois

Get recent, data-driven insights about flights from St. Louis to Illinois including ideal travel times, pricing trends, and more.

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 $320). 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 January 22, 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 January 22, 2025.

The most flights from STL to USIL are scheduled on a Wednesday (53 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (35 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 January 22, 2025.
Peruse reviews from past customers who have flown with United Airlines, Delta and Southern / Mokulele 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
8.1
Very good
4,654 reviews

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,654 reviews
Southwest
8.1
Very good
4,654 reviews

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,512 reviews
Southwest
8.1
Very good
4,654 reviews

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,975 reviews
Southwest
8.1
Very good
4,654 reviews

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,654 reviews

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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 $35. Users have also found prices from $64 and $69 on Frontier and Southwest, 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: Royal Jordanian (87%), Republic Airways (83%), Envoy Air (82%).

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

    The cheapest flight price from St. Louis to Illinois is $153. On average you can expect to pay $1,479. The most popular route, (Lambert-St Louis - Chicago O'Hare Intl), can usually be booked for $126.

  • 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 $320). 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.

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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 January 22, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$115Average$261FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$118Average$299FlexibilityNo cancel feeOn-time69%
Southern / MokuleleCheapest$118Average$183FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$168Average$283FlexibilityNo cancel feeOn-time63%
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