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Cheap flights from St. Louis to Philadelphia from $70

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 2/28. 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

Enter your travel dates to find the best prices.
Frontier Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
Frontier Logo
3:45 pm - 10:27 pm
PHL
-
STL
7h 42m
1 stop
$133Frontier
Tue, Feb 24 - Wed, Feb 25
Multiple Airlines Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
Multiple Airlines Logo
7:46 pm - 10:27 pm
PHL
-
STL
27h 41m
1 stop
$134Multiple Airlines
Tue, Feb 24 - Tue, Mar 3
Frontier Logo
3:49 pm - 11:41 am
STL
-
PHL
18h 52m
1 stop
Frontier Logo
2:09 pm - 10:27 pm
PHL
-
STL
9h 18m
1 stop
$136Frontier
Wed, Feb 25 - Tue, Mar 3
Frontier Logo
3:49 pm - 9:06 am
STL
-
PHL
16h 17m
1 stop
Frontier Logo
2:09 pm - 10:27 pm
PHL
-
STL
9h 18m
1 stop
$138Frontier
Fri, Feb 27 - Tue, Mar 3
Frontier Logo
3:49 pm - 2:44 pm
STL
-
PHL
21h 55m
1 stop
Frontier Logo
3:45 pm - 10:27 pm
PHL
-
STL
7h 42m
1 stop
$141Frontier
Mon, Feb 23 - Wed, Feb 25
Frontier Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
Frontier Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
$142Frontier
Tue, Feb 24 - Fri, Feb 27
Frontier Logo
3:49 pm - 11:41 am
STL
-
PHL
18h 52m
1 stop
Frontier Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
$145Frontier
Wed, Feb 25 - Fri, Feb 27
Frontier Logo
3:49 pm - 9:06 am
STL
-
PHL
16h 17m
1 stop
Frontier Logo
5:30 am - 6:51 am
PHL
-
STL
26h 21m
1 stop
$147Frontier
Fri, Feb 27 - Sun, Mar 1
Frontier Logo
3:49 pm - 2:44 pm
STL
-
PHL
21h 55m
1 stop
Frontier Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
$153Frontier
Mon, Feb 23 - Fri, Feb 27
Frontier Logo
8:17 pm - 11:18 am
STL
-
PHL
14h 01m
1 stop
Frontier Logo
6:40 pm - 6:51 am
PHL
-
STL
13h 11m
1 stop
$154Frontier
Sat, Feb 21 - Tue, Mar 3

Frontier flights from St. Louis to Philadelphia

Our best Frontier deals on St. Louis to Philadelphia flight tickets
Frontier
Feb 24
STL3:49 pmLambert-St Louis
19h 33m
1 stop
PHL12:22 pmPhiladelphia
Feb 25
PHL3:45 pmPhiladelphia
7h 42m
1 stop
STL10:27 pmLambert-St Louis
$133
Frontier
Feb 25
STL3:49 pmLambert-St Louis
18h 52m
1 stop
PHL11:41 amPhiladelphia
Mar 3
PHL2:09 pmPhiladelphia
9h 18m
1 stop
STL10:27 pmLambert-St Louis
$136
Frontier
Feb 27
STL3:49 pmLambert-St Louis
16h 17m
1 stop
PHL9:06 amPhiladelphia
Mar 3
PHL2:09 pmPhiladelphia
9h 18m
1 stop
STL10:27 pmLambert-St Louis
$138

American Airlines flights from St. Louis to Philadelphia

Our best American Airlines deals on St. Louis to Philadelphia flight tickets
American Airlines
Feb 7
STL6:00 amLambert-St Louis
2h 22m
PHL9:22 amPhiladelphia
Feb 15
PHL9:20 pmPhiladelphia
2h 44m
STL11:04 pmLambert-St Louis
$651
American Airlines
Feb 2
STL10:17 amLambert-St Louis
6h 38m
1 stop
PHL5:55 pmPhiladelphia
Feb 2
PHL8:47 pmPhiladelphia
2h 57m
STL10:44 pmLambert-St Louis
$719
American Airlines
Feb 6
STL10:17 amLambert-St Louis
8h 21m
1 stop
PHL7:38 pmPhiladelphia
Feb 7
PHL9:45 amPhiladelphia
2h 51m
STL11:36 amLambert-St Louis
$808

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 February 2, 2026.
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

Tue 2/24

3:49 pm-12:22 pm

1 stop19h 33m

Philadelphia

Wed 2/25

3:45 pm-10:27 pm

1 stop7h 42m

$133

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Tue 2/24

3:49 pm-12:22 pm

1 stop19h 33m

Philadelphia

Tue 3/3

7:46 pm-10:27 pm

1 stop27h 41m

$134

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 2/25

3:49 pm-11:41 am

1 stop18h 52m

Philadelphia

Tue 3/3

2:09 pm-10:27 pm

1 stop9h 18m

$136

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 2/27

3:49 pm-9:06 am

1 stop16h 17m

Philadelphia

Tue 3/3

2:09 pm-10:27 pm

1 stop9h 18m

$138

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Mon 2/23

3:49 pm-2:44 pm

1 stop21h 55m

Philadelphia

Wed 2/25

3:45 pm-10:27 pm

1 stop7h 42m

$141

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Tue 2/24

3:49 pm-12:22 pm

1 stop19h 33m

Philadelphia

Fri 2/27

7:12 pm-6:51 am

1 stop12h 39m

$142

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 2/25

3:49 pm-11:41 am

1 stop18h 52m

Philadelphia

Fri 2/27

7:12 pm-6:51 am

1 stop12h 39m

$145

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 2/27

3:49 pm-9:06 am

1 stop16h 17m

Philadelphia

Sun 3/1

5:30 am-6:51 am

1 stop26h 21m

$147

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Mon 2/23

3:49 pm-2:44 pm

1 stop21h 55m

Philadelphia

Fri 2/27

7:12 pm-6:51 am

1 stop12h 39m

$153

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Sat 2/21

8:17 pm-11:18 am

1 stop14h 01m

Philadelphia

Tue 3/3

6:40 pm-6:51 am

1 stop13h 11m

$154

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 $277, 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 $340.

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 $649. 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 $946.

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 $401. 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 $1,122.

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 $409 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 $338 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 11% 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 February 2026, prices for St. Louis to Philadelphia flights are approximately 28% 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

$331

Fastest flight time

2h 05m

Direct flights

Mon, Tue, Thu, Fri, Sat and Sun

Airports in Philadelphia

1 airport
The best one-way flight to Philadelphia from St. Louis in the past 72 hours is $331. The best round-trip flight deal from St. Louis to Philadelphia found on momondo in the last 72 hours is $447.
The fastest flight from St. Louis to Philadelphia takes 2h 05m
Direct flights go from St. Louis to Philadelphia on Monday, Tuesday, Thursday, Friday, Saturday and Sunday. There are no airlines offering direct flights.
There is 1 airport in Philadelphia. From St. Louis there are direct flights to 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 05m, 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
Spirit AirlinesPriceFrom $82Free CancellationRating
6.3
8,395 reviews
Search Spirit Airlines flights
FrontierPriceFrom $130Free CancellationRating
5.7
3,050 reviews
Search Frontier flights
American AirlinesPriceFrom $241Free CancellationRating
7.2
11,211 reviews
Search American Airlines flights
SouthwestPriceFrom $297Free CancellationRating
8.0
4,272 reviews
Search Southwest flights

  • Southwest Flights From St. Louis to Philadelphia

    Southwest flight deals from St. Louis to Philadelphia start from $297 round-trip. Over the 5 Southwest flights for this route in a normal week, average airfare is usually $420 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 11,211 reviews) operates around 14 flights from St. Louis to Philadelphia in any given week. The average American Airlines airfare for this route is around $425, with deals from around $241 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
Cape May
Rehoboth Beach
Wildwood Crest
Ocean City
King of Prussia
Cherry Hill
Newark
Dewey Beach
Reading
North Wildwood
Avalon
Dover
Lewes
Stone Harbor
Essington
Vineland
New Castle
Pottstown
Somers Point

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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