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Cheap flights from Philadelphia to St. Louis from $63

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 2/21. 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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Cheap round-trip flights

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Multiple Airlines Logo
6:01 pm - 10:34 pmPHL-STL
29h 33m1 stop
Multiple Airlines Logo
10:06 am - 11:50 pmSTL-PHL
12h 44m2 stops
$194Multiple Airlines
Find Deal
Mon, Jan 12 - Sun, Jan 18
Multiple Airlines Logo
5:15 am - 9:47 amPHL-STL
29h 32m2 stops
Multiple Airlines Logo
11:51 am - 9:07 amSTL-PHL
20h 16m1 stop
$195Multiple Airlines
Find Deal
Thu, Dec 11 - Tue, Dec 23
Frontier Logo
4:08 pm - 10:34 pmPHL-STL
7h 26m1 stop
Frontier Logo
11:00 am - 10:46 pmSTL-PHL
10h 46m1 stop
$206Frontier
Find Deal
Sat, Jan 17 - Sat, Jan 24
Frontier Logo
6:01 pm - 10:34 pmPHL-STL
29h 33m1 stop
Frontier Logo
10:06 am - 7:51 amSTL-PHL
20h 45m1 stop
$209Frontier
Find Deal
Mon, Jan 12 - Sun, Jan 18
Multiple Airlines Logo
8:36 pm - 10:14 amPHL-STL
14h 38m1 stop
Multiple Airlines Logo
3:30 pm - 2:44 pmSTL-PHL
22h 14m2 stops
$211Multiple Airlines
Find Deal
Fri, Dec 12 - Mon, Dec 15
Frontier Logo
10:00 pm - 10:33 pmPHL-STL
25h 33m1 stop
Frontier Logo
9:54 am - 10:00 amSTL-PHL
23h 06m1 stop
$217Frontier
Find Deal
Thu, Dec 11 - Sun, Dec 14
Multiple Airlines Logo
5:15 am - 9:47 amPHL-STL
29h 32m2 stops
Multiple Airlines Logo
2:47 pm - 9:17 amSTL-PHL
17h 30m1 stop
$218Multiple Airlines
Find Deal
Thu, Dec 11 - Sun, Dec 14
Multiple Airlines Logo
8:36 pm - 10:14 amPHL-STL
14h 38m1 stop
Multiple Airlines Logo
3:30 pm - 2:44 pmSTL-PHL
22h 14m2 stops
$223Multiple Airlines
Find Deal
Fri, Dec 12 - Tue, Dec 16
Multiple Airlines Logo
1:46 pm - 7:42 pmPHL-STL
6h 56m1 stop
Multiple Airlines Logo
11:51 am - 11:17 pmSTL-PHL
10h 26m1 stop
$227Multiple Airlines
Find Deal
Fri, Dec 19 - Sun, Dec 21
Multiple Airlines Logo
5:15 am - 1:52 pmPHL-STL
9h 37m1 stop
Multiple Airlines Logo
12:04 pm - 9:17 amSTL-PHL
20h 13m2 stops
$228Multiple Airlines
Find Deal
Sun, Dec 7 - Thu, Dec 11

American Airlines flights from Philadelphia to St. Louis

Our best American Airlines deals on Philadelphia to St. Louis flight tickets
American Airlines
Jan 17
PHL8:47 pmPhiladelphia
2h 57m
STL10:44 pmLambert-St Louis
Jan 20
STL11:05 amLambert-St Louis
8h 20m
1 stop
PHL8:25 pmPhiladelphia
$288
Find similar
American Airlines
Jan 17
PHL4:36 pmPhiladelphia
7h 50m
1 stop
STL11:26 pmLambert-St Louis
Jan 20
STL3:20 pmLambert-St Louis
7h 35m
1 stop
PHL11:55 pmPhiladelphia
$298
Find similar
American Airlines
Dec 18
PHL10:50 amPhiladelphia
2h 39m
STL12:29 pmLambert-St Louis
Jan 17
STL11:05 amLambert-St Louis
8h 20m
1 stop
PHL8:25 pmPhiladelphia
$304
Find similar

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Dec 11
PHL2:06 pmPhiladelphia
9h 27m
1 stop
STL10:33 pmLambert-St Louis
Dec 14
STL3:30 pmLambert-St Louis
20h 06m
1 stop
PHL12:36 pmPhiladelphia
$187
Find similar
Frontier
Jan 17
PHL2:00 pmPhiladelphia
9h 34m
1 stop
STL10:34 pmLambert-St Louis
Jan 24
STL11:00 amLambert-St Louis
10h 46m
1 stop
PHL10:46 pmPhiladelphia
$206
Find similar
Frontier
Jan 12
PHL6:01 pmPhiladelphia
29h 33m
1 stop
STL10:34 pmLambert-St Louis
Jan 18
STL10:06 amLambert-St Louis
20h 45m
1 stop
PHL7:51 amPhiladelphia
$209
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 November 24, 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

Mon 1/12

6:01 pm-10:34 pm

1 stop29h 33m

Lambert-St Louis

Sun 1/18

10:06 am-11:50 pm

2 stops12h 44m

$194

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 12/11

5:15 am-9:47 am

2 stops29h 32m

Lambert-St Louis

Tue 12/23

11:51 am-9:07 am

1 stop20h 16m

$195

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 1/17

4:08 pm-10:34 pm

1 stop7h 26m

Lambert-St Louis

Sat 1/24

11:00 am-10:46 pm

1 stop10h 46m

$206

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 1/12

6:01 pm-10:34 pm

1 stop29h 33m

Lambert-St Louis

Sun 1/18

10:06 am-7:51 am

1 stop20h 45m

$209

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 12/12

8:36 pm-10:14 am

1 stop14h 38m

Lambert-St Louis

Mon 12/15

3:30 pm-2:44 pm

2 stops22h 14m

$211

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 12/11

10:00 pm-10:33 pm

1 stop25h 33m

Lambert-St Louis

Sun 12/14

9:54 am-10:00 am

1 stop23h 06m

$217

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 12/11

5:15 am-9:47 am

2 stops29h 32m

Lambert-St Louis

Sun 12/14

2:47 pm-9:17 am

1 stop17h 30m

$218

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 12/12

8:36 pm-10:14 am

1 stop14h 38m

Lambert-St Louis

Tue 12/16

3:30 pm-2:44 pm

2 stops22h 14m

$223

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 12/19

1:46 pm-7:42 pm

1 stop6h 56m

Lambert-St Louis

Sun 12/21

11:51 am-11:17 pm

1 stop10h 26m

$227

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 12/7

5:15 am-1:52 pm

1 stop9h 37m

Lambert-St Louis

Thu 12/11

12:04 pm-9:17 am

2 stops20h 13m

$228

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 11% 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 24m

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 24m
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 39m 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
8,158 reviews
Search Spirit Airlines flights
FrontierPriceFrom $130Free CancellationRating
5.8
3,096 reviews
Search Frontier flights
American AirlinesPriceFrom $241Free CancellationRating
7.2
11,042 reviews
Search American Airlines flights
DeltaPriceFrom $259Free CancellationRating
7.9
7,998 reviews
Search Delta flights
SouthwestPriceFrom $277Free CancellationRating
8.0
4,252 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 10 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 11,042 user reviews) flies into St. Louis from Philadelphia 14 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

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
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