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Cheap flights from Philadelphia to St. Louis from $44

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Philadelphia to St. Louis departing on 12/19. 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 Philadelphia to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
5:10 am - 9:40 amPHL-STL
5h 30m1 stop
Frontier Logo
7:43 pm - 5:31 amSTL-PHL
8h 48m1 stop
$238Frontier
Find Deal
dom., dic. 28 - vie., ene. 2
Frontier Logo
6:19 am - 9:07 amPHL-STL
27h 48m1 stop
Frontier Logo
4:13 pm - 7:28 pmSTL-PHL
26h 15m1 stop
$240Frontier
Find Deal
lun., nov. 17 - jue., nov. 20
Frontier Logo
8:00 am - 10:02 amPHL-STL
27h 02m2 stops
Frontier Logo
3:14 pm - 11:23 amSTL-PHL
19h 09m1 stop
$242Frontier
Find Deal
jue., nov. 20 - dom., nov. 23
Frontier Logo
6:50 pm - 11:01 pmPHL-STL
29h 11m2 stops
Frontier Logo
4:13 pm - 7:32 amSTL-PHL
14h 19m1 stop
$247Frontier
Find Deal
mar., nov. 18 - dom., nov. 23
Multiple Airlines Logo
4:35 pm - 9:58 amPHL-STL
18h 23m1 stop
Multiple Airlines Logo
7:03 pm - 4:52 pmSTL-PHL
20h 49m2 stops
$251Multiple Airlines
Find Deal
mié., nov. 26 - lun., dic. 1
Frontier Logo
6:19 am - 9:07 amPHL-STL
27h 48m1 stop
Frontier Logo
4:13 pm - 4:35 pmSTL-PHL
23h 22m1 stop
$254Frontier
Find Deal
lun., nov. 17 - jue., nov. 20
Multiple Airlines Logo
9:54 am - 11:57 pmPHL-STL
15h 03m2 stops
Multiple Airlines Logo
2:47 pm - 9:17 amSTL-PHL
17h 30m1 stop
$256Multiple Airlines
Find Deal
lun., dic. 1 - dom., dic. 7
Frontier Logo
6:35 pm - 11:01 pmPHL-STL
5h 26m1 stop
Frontier Logo
7:43 pm - 4:45 amSTL-PHL
8h 02m1 stop
$261Frontier
Find Deal
mié., nov. 19 - vie., nov. 21
Frontier Logo
8:42 pm - 10:14 amPHL-STL
38h 32m2 stops
Frontier Logo
10:42 am - 7:30 pmSTL-PHL
7h 48m1 stop
$262Frontier
Find Deal
lun., dic. 1 - vie., dic. 5
Frontier Logo
8:00 am - 10:05 amPHL-STL
27h 05m1 stop
Frontier Logo
7:24 pm - 11:20 amSTL-PHL
14h 56m1 stop
$264Frontier
Find Deal
mar., nov. 18 - mié., nov. 19

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Dec 28
PHL5:10 amPhiladelphia
5h 30m
1 stop
STL9:40 amLambert-St Louis
Jan 2
STL7:43 pmLambert-St Louis
8h 48m
1 stop
PHL5:31 amPhiladelphia
$238
Find similar
Frontier
Feb 9
PHL12:32 pmPhiladelphia
11h 01m
1 stop
STL10:33 pmLambert-St Louis
Feb 12
STL10:42 amLambert-St Louis
6h 59m
1 stop
PHL6:41 pmPhiladelphia
$240
Find similar
Frontier
Nov 20
PHL8:00 amPhiladelphia
27h 02m
2 stops
STL10:02 amLambert-St Louis
Nov 23
STL3:14 pmLambert-St Louis
19h 09m
1 stop
PHL11:23 amPhiladelphia
$242
Find similar

Southwest flights from Philadelphia to St. Louis

Our best Southwest deals on Philadelphia to St. Louis flight tickets
Southwest
Jan 10
PHL8:05 amPhiladelphia
2h 35m
STL9:40 amLambert-St Louis
Jan 17
STL8:55 amLambert-St Louis
2h 10m
PHL12:05 pmPhiladelphia
$352
Find similar
Southwest
Dec 6
PHL8:15 amPhiladelphia
2h 30m
STL9:45 amLambert-St Louis
Dec 10
STL8:15 amLambert-St Louis
2h 10m
PHL11:25 amPhiladelphia
$353
Find similar
Southwest
Jan 17
PHL4:40 pmPhiladelphia
6h 25m
1 stop
STL10:05 pmLambert-St Louis
Jan 24
STL8:55 amLambert-St Louis
2h 10m
PHL12:05 pmPhiladelphia
$362
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Philadelphia 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 13, 2025.
Use the filters below to find and compare flights from Philadelphia to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

dom. 12/28

5:10 am-9:40 am

1 stop5h 30m

Lambert-St Louis

vie. 1/2

7:43 pm-5:31 am

1 stop8h 48m

$238

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

lun. 11/17

6:19 am-9:07 am

1 stop27h 48m

Lambert-St Louis

jue. 11/20

4:13 pm-7:28 pm

1 stop26h 15m

$240

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

jue. 11/20

8:00 am-10:02 am

2 stops27h 02m

Lambert-St Louis

dom. 11/23

3:14 pm-11:23 am

1 stop19h 09m

$242

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mar. 11/18

6:50 pm-11:01 pm

2 stops29h 11m

Lambert-St Louis

dom. 11/23

4:13 pm-7:32 am

1 stop14h 19m

$247

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mié. 11/26

4:35 pm-9:58 am

1 stop18h 23m

Lambert-St Louis

lun. 12/1

7:03 pm-4:52 pm

2 stops20h 49m

$251

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

lun. 11/17

6:19 am-9:07 am

1 stop27h 48m

Lambert-St Louis

jue. 11/20

4:13 pm-4:35 pm

1 stop23h 22m

$254

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

lun. 12/1

9:54 am-11:57 pm

2 stops15h 03m

Lambert-St Louis

dom. 12/7

2:47 pm-9:17 am

1 stop17h 30m

$256

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mié. 11/19

6:35 pm-11:01 pm

1 stop5h 26m

Lambert-St Louis

vie. 11/21

7:43 pm-4:45 am

1 stop8h 02m

$261

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

lun. 12/1

8:42 pm-10:14 am

2 stops38h 32m

Lambert-St Louis

vie. 12/5

10:42 am-7:30 pm

1 stop7h 48m

$262

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mar. 11/18

8:00 am-10:05 am

1 stop27h 05m

Lambert-St Louis

mié. 11/19

7:24 pm-11:20 am

1 stop14h 56m

$264

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 Philadelphia 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, September is the cheapest month to fly from Philadelphia to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $317. The month of August is another great option to travel to St. Louis, with average flight prices from Philadelphia averaging around $320.

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 Wednesday when prices can be found for as low as $388. 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 Sunday because tickets tend to average around $479. 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 Philadelphia in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $384 when looking at flights departing in the afternoon. In the evening is when there is more demand to fly to St. Louis, so prices are often more expensive at around $428 per ticket.

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

Fly from Philadelphia to Lambert-St Louis for the best Philadelphia - 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 Philadelphia when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $403 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Philadelphia for as low as $338 on momondo.

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

There are 2 cabin classes available to choose from on Philadelphia 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.

How have Philadelphia to St. Louis flight prices changed over time?

As of November 2025, prices for Philadelphia to St. Louis flights are approximately 23% cheaper when compared to flights at the same time last year.

When to book flights from Philadelphia to St. Louis

Are you open to changing your travel dates? Check out the ideal times to fly from Philadelphia to St. Louis according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Philadelphia to St. Louis (PHL to STL) flight deals and tips

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

Best Price Found

$157

Fastest flight time

2h 30m

Direct flights

Every day

Airports in St. Louis

1 airport
The best one-way flight to St. Louis from Philadelphia in the past 72 hours is $157. The best round-trip flight deal from Philadelphia to St. Louis found on momondo in the last 72 hours is $356.
The fastest flight from Philadelphia to St. Louis takes 2h 30m
Direct flights go from Philadelphia to St. Louis every day.
There is 1 airport near St. Louis: Lambert-St Louis (STL)
Search flight deals

  • How far is Philadelphia to Lambert-St Louis by plane?

    There are 808.1 mi between Philadelphia and Lambert-St Louis. Typically, this will take 2h 30m by plane in normal conditions.

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

    Prices for flights from Philadelphia Airport to Lambert-St Louis Airport were last updated today.

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

  • How old do you have to be to fly from Philadelphia Airport 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 Philadelphia Airport to Lambert-St Louis Airport.

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

    The travel and health documents required for your trip to Lambert-St Louis Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Lambert-St Louis Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

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

  • What is the most popular airline from Philadelphia to St. Louis?

Best airlines flying from Philadelphia to St. Louis

Compare and see reviews for airlines that fly from Philadelphia to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
Spirit AirlinesPriceFrom $95Free CancellationRating
6.3
8,139 reviews
Search Spirit Airlines flights
FrontierPriceFrom $130Free CancellationRating
5.8
3,109 reviews
Search Frontier flights
American AirlinesPriceFrom $241Free CancellationRating
7.2
11,051 reviews
Search American Airlines flights
DeltaPriceFrom $259Free CancellationRating
7.9
8,007 reviews
Search Delta flights
SouthwestPriceFrom $277Free CancellationRating
8.0
4,242 reviews
Search Southwest flights

  • Southwest Flights From Philadelphia to St. Louis

    The lowest priced Southwest flight from Philadelphia to St. Louis from the last 72 hours was $277. Generally, Southwest has 17 flights on this route every week with an average price of $422. Southwest is rated 8.0/10 by our users.

  • American Airlines Flights From Philadelphia to St. Louis

    $241 is the best American Airlines flight deal from Philadelphia to St. Louis found on momondo over the last 72 hours. The average American Airlines ticket price found was closer to $417, however, with flight time and availability significantly affecting the price. American Airlines (7.2/10 from 11,051 user reviews) flies into St. Louis from Philadelphia 17 times in an average week so prices can vary.

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 Philadelphia to St. Louis?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Philadelphia to St. Louis for you.

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

Yes. All flights to St. Louis from Philadelphia on momondo can be compared and filtered by various policies on offer, including flexible booking.

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

momondo provides multiple filters to help you find the best flight to St. Louis from Philadelphia. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

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

If you are simply researching potential flights to St. Louis, momondo offers a useful price alert feature which will track prices for flights to St. Louis from Philadelphia and alert you when they change.

An easier way to manage your St. Louis trip

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