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Cheap flights from Illinois to St. Louis from $49

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Illinois to St. Louis departing on 12/25. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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0 bags

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Find the cheapest flights from Illinois to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
United Airlines Logo
12:56 pm - 2:26 pmORD-STL
1h 30mnonstop
United Airlines Logo
6:35 pm - 8:19 pmSTL-ORD
1h 44mnonstop
$127United Airlines
Find Deal
mié., dic. 24 - mié., dic. 24
Frontier Logo
12:07 pm - 6:44 pmORD-STL
6h 37m1 stop
Frontier Logo
4:45 pm - 10:41 amSTL-ORD
17h 56m1 stop
$131Frontier
Find Deal
vie., ene. 23 - dom., ene. 25
Southwest Logo
12:30 pm - 1:45 pmMDW-STL
1h 15mnonstop
Southwest Logo
5:55 pm - 7:05 pmSTL-MDW
1h 10mnonstop
$138Southwest
Find Deal
jue., ene. 15 - dom., ene. 18
American Airlines Logo
7:14 am - 8:48 amORD-STL
1h 34mnonstop
American Airlines Logo
6:46 pm - 8:20 pmSTL-ORD
1h 34mnonstop
$141American Airlines
Find Deal
mié., dic. 31 - mar., ene. 13
Frontier Logo
6:10 am - 2:48 pmMDW-STL
8h 38m1 stop
Frontier Logo
8:50 am - 11:09 pmSTL-MDW
14h 19m1 stop
$142Frontier
Find Deal
dom., ene. 11 - lun., ene. 12
Multiple Airlines Logo
10:39 am - 11:33 pmORD-STL
12h 54m1 stop
Multiple Airlines Logo
10:42 am - 11:35 pmSTL-ORD
12h 53m1 stop
$148Multiple Airlines
Find Deal
mar., ene. 20 - vie., feb. 20
American Airlines Logo
7:14 am - 8:48 amORD-STL
1h 34mnonstop
American Airlines Logo
11:05 am - 12:34 pmSTL-ORD
1h 29mnonstop
$151American Airlines
Find Deal
mié., dic. 31 - mar., ene. 13
Southwest Logo
9:50 am - 1:00 pmMDW-STL
3h 10m1 stop
Southwest Logo
2:30 pm - 3:40 pmSTL-MDW
1h 10mnonstop
$156Southwest
Find Deal
jue., ene. 1 - lun., ene. 5
Delta Logo
4:01 pm - 10:16 pmORD-STL
6h 15m1 stop
Delta Logo
1:22 pm - 7:38 pmSTL-ORD
6h 16m1 stop
$157Delta
Find Deal
mié., dic. 24 - jue., dic. 25
Multiple Airlines Logo
12:44 pm - 10:34 pmORD-STL
9h 50m1 stop
Multiple Airlines Logo
10:06 am - 7:51 pmSTL-ORD
9h 45m1 stop
$160Multiple Airlines
Find Deal
jue., ene. 15 - dom., ene. 18

United Airlines flights from Illinois to St. Louis

Our best United Airlines deals on Illinois to St. Louis flight tickets
United Airlines
Dec 24
ORD12:56 pmChicago O'Hare Intl
1h 30m
STL2:26 pmLambert-St Louis
Dec 24
STL6:35 pmLambert-St Louis
1h 44m
ORD8:19 pmChicago O'Hare Intl
$127
Find similar
United Airlines
Dec 17
ORD9:23 pmChicago O'Hare Intl
1h 22m
STL10:45 pmLambert-St Louis
Dec 24
STL9:55 amLambert-St Louis
1h 35m
ORD11:30 amChicago O'Hare Intl
$147
Find similar
United Airlines
Jan 15
ORD1:00 pmChicago O'Hare Intl
1h 30m
STL2:30 pmLambert-St Louis
Jan 18
STL8:05 amLambert-St Louis
1h 35m
ORD9:40 amChicago O'Hare Intl
$198
Find similar

Frontier flights from Illinois to St. Louis

Our best Frontier deals on Illinois to St. Louis flight tickets
Frontier
Jan 23
ORD12:07 pmChicago O'Hare Intl
6h 37m
1 stop
STL6:44 pmLambert-St Louis
Jan 25
STL4:45 pmLambert-St Louis
17h 56m
1 stop
ORD10:41 amChicago O'Hare Intl
$131
Find similar
Frontier
Jan 11
MDW6:10 amChicago Midway
8h 38m
1 stop
STL2:48 pmLambert-St Louis
Jan 12
STL8:50 amLambert-St Louis
14h 19m
1 stop
MDW11:09 pmChicago Midway
$142
Find similar
Frontier
Dec 11
MDW7:23 pmChicago Midway
14h 24m
1 stop
STL9:47 amLambert-St Louis
Dec 14
STL10:42 amLambert-St Louis
23h 10m
1 stop
MDW9:52 amChicago Midway
$147
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Illinois to St. Louis 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, momondo users made 832,500 searches. Data last updated noviembre 20, 2025.
Use the filters below to find and compare flights from Illinois to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

mié. 12/24

12:56 pm-2:26 pm

Nonstop1h 30m

Lambert-St Louis

mié. 12/24

6:35 pm-8:19 pm

Nonstop1h 44m

$127

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

vie. 1/23

12:07 pm-6:44 pm

1 stop6h 37m

Lambert-St Louis

dom. 1/25

4:45 pm-10:41 am

1 stop17h 56m

$131

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

jue. 1/15

12:30 pm-1:45 pm

Nonstop1h 15m

Lambert-St Louis

dom. 1/18

5:55 pm-7:05 pm

Nonstop1h 10m

$138

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

mié. 12/31

7:14 am-8:48 am

Nonstop1h 34m

Lambert-St Louis

mar. 1/13

6:46 pm-8:20 pm

Nonstop1h 34m

$141

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

dom. 1/11

6:10 am-2:48 pm

1 stop8h 38m

Lambert-St Louis

lun. 1/12

8:50 am-11:09 pm

1 stop14h 19m

$142

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

mar. 1/20

10:39 am-11:33 pm

1 stop12h 54m

Lambert-St Louis

vie. 2/20

10:42 am-11:35 pm

1 stop12h 53m

$148

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

mié. 12/31

7:14 am-8:48 am

Nonstop1h 34m

Lambert-St Louis

mar. 1/13

11:05 am-12:34 pm

Nonstop1h 29m

$151

ChicagoSt. Louis

MDW - STL

MDWSTL

Chicago Midway

jue. 1/1

9:50 am-1:00 pm

1 stop3h 10m

Lambert-St Louis

lun. 1/5

2:30 pm-3:40 pm

Nonstop1h 10m

$156

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

mié. 12/24

4:01 pm-10:16 pm

1 stop6h 15m

Lambert-St Louis

jue. 12/25

1:22 pm-7:38 pm

1 stop6h 16m

$157

ChicagoSt. Louis

ORD - STL

ORDSTL

Chicago O'Hare Intl

jue. 1/15

12:44 pm-10:34 pm

1 stop9h 50m

Lambert-St Louis

dom. 1/18

10:06 am-7:51 pm

1 stop9h 45m

$160

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Illinois to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to St. Louis?

In general, August is the cheapest month to fly from Illinois to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $257. The month of April is another great option to travel to St. Louis, with average flight prices from Illinois averaging around $269.

What is the cheapest day to depart on your flight to St. Louis?

The cheapest day to depart on your flight to St. Louis is on a Thursday when prices can be found for as low as $308. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Monday because tickets tend to average around $510. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

What is the cheapest time of day to depart on your flight to St. Louis?

Flying to St. Louis from Illinois at noon is the least expensive time of day to depart. momondo users have found prices as low as $314 when looking at flights departing at noon. In the morning is when there is more demand to fly to St. Louis, so prices are often more expensive at around $432 per ticket.

What is the cheapest Illinois to Lambert-St Louis flight route?

Fly from Chicago O'Hare Intl to Lambert-St Louis for the best Illinois - Lambert-St Louis flight prices

How far in advance should I book a flight to St. Louis?

You are more likely to see cheaper flights to St. Louis from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $294 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Illinois for as low as $142 on momondo.

What cabin class options are available on Illinois to Lambert-St Louis flights?

There are 4 cabin classes available to choose from on Illinois to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Illinois to St. Louis flights?

No. A direct flight is the cheapest option for a flight between Illinois to St. Louis.

Cheap Illinois to St. Louis flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Illinois to St. Louis

Best Price Found

$128

Fastest flight time

1h 10m

Direct flights

Every day

Airports in St. Louis

1 airport
The best one-way flight to St. Louis from Illinois in the past 72 hours is $128. The best round-trip flight deal from Illinois to St. Louis found on momondo in the last 72 hours is $61.
The fastest flight from Illinois to St. Louis takes 1h 10m
Direct flights go from Illinois to St. Louis every day.
There is 1 airport near St. Louis: Lambert-St Louis (STL)
Search flight deals

  • When did momondo last update prices for flights from Illinois to Lambert-St Louis Airport?

    Prices for flights from Illinois to Lambert-St Louis Airport refresh daily.

  • How many operators does momondo search for flights from Illinois to Lambert-St Louis Airport?

  • How old do you have to be to fly from Illinois to Lambert-St Louis Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Illinois to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The required travel and health documents for your Lambert-St Louis Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Lambert-St Louis Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

  • What is the most popular plane model from Illinois to St. Louis?

Best airlines flying from Illinois to St. Louis

Compare and see reviews for airlines that fly from Illinois to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
SouthwestPriceFrom $77Free CancellationRating
8.0
4,251 reviews
Search Southwest flights
American AirlinesPriceFrom $115Free CancellationRating
7.2
11,047 reviews
Search American Airlines flights
Southern / MokulelePriceFrom $145Free CancellationRating
0.0
0 reviews
Search Southern / Mokulele flights
United AirlinesPriceFrom $152Free CancellationRating
7.4
9,029 reviews
Search United Airlines flights

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Hermann
Fairview Heights
Florissant
Maryland Heights
O'Fallon
Wentzville
Fenton
Collinsville
St. Peters
Alton
Farmington
Festus
Glencoe
Edwardsville
Clayton
Eureka
Litchfield
Shrewsbury

Why use momondo?

Why should I use momondo to find a flight deal from Illinois to St. Louis?

It is quick and easy to find Illinois to St. Louis flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to St. Louis that suits you.

Can I find flights from Illinois to St. Louis with flexible booking policies on momondo?

All flight searches from Illinois to St. Louis on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from Illinois to St. Louis?

Once all potential Illinois to St. Louis flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

I’m not ready to book a flight from Illinois to St. Louis right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to St. Louis from Illinois. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

An easier way to manage your St. Louis trip

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