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Cheap flights from St. Louis to Philadelphia from $59

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Philadelphia departing on 9/18. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Find the cheapest flights from St. Louis to Philadelphia

Cheap round-trip flights

Spirit Airlines Logo
2:30 pm - 8:49 pmSTL-PHL
5h 19m1 stop
Spirit Airlines Logo
7:00 am - 1:32 pmPHL-STL
7h 32m1 stop
$146Spirit Airlines
Find Deal
Fri, Aug 22 - Sun, Aug 24
Spirit Airlines Logo
2:30 pm - 8:49 pmSTL-PHL
5h 19m1 stop
Spirit Airlines Logo
7:00 am - 1:32 pmPHL-STL
7h 32m1 stop
$147Spirit Airlines
Find Deal
Fri, Aug 22 - Sun, Aug 24
Logo
3:02 pm - 12:20 amSTL-PHL
8h 18m1 stop
Logo
7:00 am - 1:32 pmPHL-STL
7h 32m1 stop
$194
Find Deal
Sat, Aug 23 - Mon, Aug 25
Logo
8:00 am - 3:31 pmSTL-PHL
6h 31m1 stop
Logo
7:00 am - 1:32 pmPHL-STL
7h 32m1 stop
$201
Find Deal
Tue, Aug 19 - Thu, Aug 21
Frontier Logo
5:11 pm - 12:38 amSTL-PHL
6h 27m1 stop
Frontier Logo
4:12 pm - 10:46 pmPHL-STL
7h 34m1 stop
$215Frontier
Find Deal
Thu, Dec 4 - Mon, Dec 8
Southwest Logo
11:55 am - 3:10 pmSTL-PHL
2h 15mnonstop
Southwest Logo
7:50 am - 9:10 amPHL-STL
2h 20mnonstop
$217Southwest
Find Deal
Sat, Aug 23 - Mon, Aug 25
Frontier Logo
5:40 pm - 8:02 amSTL-PHL
13h 22m1 stop
Frontier Logo
8:00 am - 1:46 pmPHL-STL
30h 46m1 stop
$225Frontier
Find Deal
Sat, Aug 16 - Sat, Aug 23
Southwest Logo
6:25 am - 4:00 pmSTL-PHL
8h 35m2 stops
Southwest Logo
4:45 pm - 6:05 pmPHL-STL
2h 20mnonstop
$232Southwest
Find Deal
Tue, Sep 16 - Wed, Sep 17
American Airlines Logo
4:54 pm - 8:14 pmSTL-PHL
2h 20mnonstop
American Airlines Logo
7:05 pm - 8:47 pmPHL-STL
2h 42mnonstop
$234American Airlines
Find Deal
Thu, Aug 28 - Tue, Sep 2
American Airlines Logo
7:32 am - 12:45 pmSTL-PHL
4h 13m1 stop
American Airlines Logo
10:45 am - 12:23 pmPHL-STL
2h 38mnonstop
$244American Airlines
Find Deal
Thu, Aug 28 - Wed, Sep 3

American Airlines flights from St. Louis to Philadelphia

Our best American Airlines deals on St. Louis to Philadelphia flight tickets
American Airlines
Aug 28
STL4:54 pmLambert-St Louis
2h 20m
PHL8:14 pmPhiladelphia
Sep 2
PHL7:05 pmPhiladelphia
2h 42m
STL8:47 pmLambert-St Louis
$234
Find similar
American Airlines
Aug 28
STL7:32 amLambert-St Louis
4h 13m
1 stop
PHL12:45 pmPhiladelphia
Sep 3
PHL10:45 amPhiladelphia
2h 38m
STL12:23 pmLambert-St Louis
$244
Find similar
American Airlines
Sep 22
STL1:03 pmLambert-St Louis
2h 20m
PHL4:23 pmPhiladelphia
Sep 25
PHL7:19 pmPhiladelphia
2h 47m
STL9:06 pmLambert-St Louis
$251
Find similar

Spirit Airlines flights from St. Louis to Philadelphia

Our best Spirit Airlines deals on St. Louis to Philadelphia flight tickets
Spirit Airlines
Aug 22
STL2:30 pmLambert-St Louis
5h 19m
1 stop
PHL8:49 pmPhiladelphia
Aug 24
PHL7:00 amPhiladelphia
7h 32m
1 stop
STL1:32 pmLambert-St Louis
$146
Find similar
Spirit Airlines
Aug 22
STL2:30 pmLambert-St Louis
5h 19m
1 stop
PHL8:49 pmPhiladelphia
Aug 24
PHL7:00 amPhiladelphia
7h 32m
1 stop
STL1:32 pmLambert-St Louis
$147
Find similar
Spirit Airlines
Sep 25
STL12:05 pmLambert-St Louis
8h 34m
1 stop
PHL9:39 pmPhiladelphia
Sep 28
PHL6:35 amPhiladelphia
5h 15m
1 stop
STL10:50 amLambert-St Louis
$149
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Philadelphia 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 July 31, 2025.
Use the filters below to find and compare flights from St. Louis to Philadelphia that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 8/22

2:30 pm-8:49 pm

1 stop5h 19m

Philadelphia

Sun 8/24

7:00 am-1:32 pm

1 stop7h 32m

$146

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 8/22

2:30 pm-8:49 pm

1 stop5h 19m

Philadelphia

Sun 8/24

7:00 am-1:32 pm

1 stop7h 32m

$147

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Sat 8/23

3:02 pm-12:20 am

1 stop8h 18m

Philadelphia

Mon 8/25

7:00 am-1:32 pm

1 stop7h 32m

$194

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Tue 8/19

8:00 am-3:31 pm

1 stop6h 31m

Philadelphia

Thu 8/21

7:00 am-1:32 pm

1 stop7h 32m

$201

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Thu 12/4

5:11 pm-12:38 am

1 stop6h 27m

Philadelphia

Mon 12/8

4:12 pm-10:46 pm

1 stop7h 34m

$215

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Sat 8/23

11:55 am-3:10 pm

Nonstop2h 15m

Philadelphia

Mon 8/25

7:50 am-9:10 am

Nonstop2h 20m

$217

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Sat 8/16

5:40 pm-8:02 am

1 stop13h 22m

Philadelphia

Sat 8/23

8:00 am-1:46 pm

1 stop30h 46m

$225

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Tue 9/16

6:25 am-4:00 pm

2 stops8h 35m

Philadelphia

Wed 9/17

4:45 pm-6:05 pm

Nonstop2h 20m

$232

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Thu 8/28

4:54 pm-8:14 pm

Nonstop2h 20m

Philadelphia

Tue 9/2

7:05 pm-8:47 pm

Nonstop2h 42m

$234

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Thu 8/28

7:32 am-12:45 pm

1 stop4h 13m

Philadelphia

Wed 9/3

10:45 am-12:23 pm

Nonstop2h 38m

$244

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 Philadelphia from

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

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 Philadelphia?

The cheapest month to fly to Philadelphia from St. Louis is in August. Flight prices, which tend to average around $246, are often lower during this time because this is during the off-season. The month of September is another great option to travel to Philadelphia, with average flight prices from St. Louis averaging around $265.

What is the cheapest day to depart on your flight to Philadelphia?

The cheapest day to depart from St. Louis to Philadelphia is on a Thursday. Travelers who choose to depart for Philadelphia on a Thursday will often find tickets for as low as $654. On the other hand, Sunday is the most expensive day to depart from St. Louis because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $917.

What is the cheapest time of day to depart on your flight to Philadelphia?

According to our data, the cheapest time of day to fly to Philadelphia is in the evening. momondo users have found flights departing from St. Louis to Philadelphia in the evening for as low as $405. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. In contrast, the most expensive time of day to depart to Philadelphia is at noon when prices are around $1,163.

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

Fly from Lambert-St Louis to Philadelphia for the best Lambert-St Louis - Philadelphia flight prices

How far in advance should I book a flight to Philadelphia?

You are more likely to see cheaper flights to Philadelphia from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Philadelphia for around $366 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Philadelphia from St. Louis for as low as $285 on momondo.

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

There are 4 cabin classes available to choose from on Lambert-St Louis to Philadelphia 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 St. Louis to Philadelphia flights?

You could potentially save up to 18% on your flight if you consider stops on a St. Louis to Philadelphia flight.

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

As of July 2025, prices for St. Louis to Philadelphia flights are approximately 51% cheaper when compared to flights at the same time last year.

When to book flights from St. Louis to Philadelphia

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

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

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

Best Price Found

$59

Fastest flight time

2h 05m

Direct flights

Every day

Airports in Philadelphia

1 airport
The best one-way flight to Philadelphia from St. Louis in the past 72 hours is $59. The best round-trip flight deal from St. Louis to Philadelphia found on momondo in the last 72 hours is $146.
The fastest flight from St. Louis to Philadelphia takes 2h 05m
Direct flights go from St. Louis to Philadelphia every day.
There is 1 airport near Philadelphia: Philadelphia (PHL)
Search flight deals

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

    The distance between Lambert-St Louis and Philadelphia is about 808.1 mi. Flights usually cover this in 2h 10m, depending on flying conditions and air traffic around both airports.

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

    Prices for flights from Lambert-St Louis Airport to Philadelphia Airport are refreshed on a daily basis.

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

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

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Lambert-St Louis Airport to Philadelphia Airport.

  • What documentation or ID do you need to fly to Philadelphia Airport?

    The travel and health documents you'll need for your trip to Philadelphia Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Philadelphia Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

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

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

Best airlines flying from St. Louis to Philadelphia

Compare and see reviews for airlines that fly from St. Louis to Philadelphia with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $63Free CancellationRating
5.9
3,239 reviews
Search Frontier flights
DeltaPriceFrom $196Free CancellationRating
8.0
7,981 reviews
Search Delta flights
American AirlinesPriceFrom $200Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
SouthwestPriceFrom $284Free CancellationRating
8.0
4,246 reviews
Search Southwest flights

  • Southwest Flights From St. Louis to Philadelphia

    Southwest flight deals from St. Louis to Philadelphia start from $284 round-trip. Over the 5 Southwest flights for this route in a normal week, average airfare is usually $410 round-trip - but some users have found much cheaper deals with momondo.

  • American Airlines Flights From St. Louis to Philadelphia

    American Airlines (7.2/10 from 10,000 reviews) operates around 14 flights from St. Louis to Philadelphia in any given week. The average American Airlines airfare for this route is around $389, with deals from around $200 rare but found on momondo. Referenced prices are for round-trip St. Louis to Philadelphia flight searches in the last 72 hours.

Traveling to a place near Philadelphia?

Book flights to Philadelphia if you plan to visit one of these locations
Wildwood
Rehoboth Beach
Cape May
Ocean City
Wildwood Crest
King of Prussia
Reading
Dewey Beach
Newark
Dover
North Wildwood
Cherry Hill
Lewes
Avalon
Stone Harbor
Vineland
Exton
Essington
New Castle
Pottstown

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from St. Louis to Philadelphia. momondo saves you time and could save you money on your trip.

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

momondo does allow users to show only those flights to Philadelphia from St. Louis which offer a flexible booking policy as well as other useful filters and features.

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

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from St. Louis to Philadelphia.

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

If you are not ready to book a flight from St. Louis to Philadelphia now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Philadelphia and let you know when they change.

An easier way to manage your Philadelphia 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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