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Cheap flights from St. Louis to Philadelphia from $55

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 11/13. 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

Enter your travel dates to find the best prices.
Frontier Logo
2:12 pm - 9:22 pmSTL-PHL
6h 10m1 stop
Frontier Logo
5:05 am - 1:17 pmPHL-STL
9h 12m1 stop
$110Frontier
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Thu, Nov 13 - Mon, Nov 17
Frontier Logo
2:12 pm - 9:22 pmSTL-PHL
6h 10m1 stop
Frontier Logo
6:50 pm - 1:17 pmPHL-STL
19h 27m1 stop
$111Frontier
Find Deal
Thu, Nov 13 - Sat, Nov 15
Frontier Logo
7:43 pm - 5:31 amSTL-PHL
8h 48m1 stop
Frontier Logo
8:00 pm - 10:33 pmPHL-STL
27h 33m1 stop
$125Frontier
Find Deal
Fri, Dec 12 - Sat, Jan 10
Frontier Logo
5:05 pm - 1:24 amSTL-PHL
7h 19m1 stop
Frontier Logo
5:05 am - 1:17 pmPHL-STL
9h 12m1 stop
$127Frontier
Find Deal
Fri, Nov 14 - Mon, Nov 17
Frontier Logo
10:42 am - 7:30 pmSTL-PHL
7h 48m1 stop
Frontier Logo
8:36 pm - 10:14 amPHL-STL
14h 38m1 stop
$139Frontier
Find Deal
Fri, Dec 5 - Sun, Dec 7
Frontier Logo
4:56 pm - 12:19 amSTL-PHL
6h 23m1 stop
Frontier Logo
5:05 am - 1:17 pmPHL-STL
9h 12m1 stop
$143Frontier
Find Deal
Fri, Nov 14 - Mon, Nov 17
Frontier Logo
3:30 pm - 12:36 pmSTL-PHL
20h 06m1 stop
Frontier Logo
8:36 pm - 10:14 amPHL-STL
14h 38m1 stop
$145Frontier
Find Deal
Wed, Dec 3 - Fri, Dec 5
Frontier Logo
7:45 pm - 4:49 amSTL-PHL
8h 04m1 stop
Frontier Logo
7:00 am - 5:22 pmPHL-STL
11h 22m1 stop
$163Frontier
Find Deal
Wed, Nov 12 - Sun, Nov 16
Multiple Airlines Logo
7:24 pm - 3:04 pmSTL-PHL
18h 40m1 stop
Multiple Airlines Logo
8:54 pm - 8:57 amPHL-STL
13h 03m1 stop
$165Multiple Airlines
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Wed, Nov 19 - Fri, Nov 21
American Airlines Logo
6:00 am - 9:19 amSTL-PHL
2h 19mnonstop
American Airlines Logo
10:25 am - 4:06 pmPHL-STL
6h 41m1 stop
$294American Airlines
Find Deal
Wed, Dec 10 - Wed, Dec 10

Frontier flights from St. Louis to Philadelphia

Our best Frontier deals on St. Louis to Philadelphia flight tickets
Frontier
Nov 13
STL2:12 pmLambert-St Louis
6h 10m
1 stop
PHL9:22 pmPhiladelphia
Nov 17
PHL5:05 amPhiladelphia
9h 12m
1 stop
STL1:17 pmLambert-St Louis
$110
Find similar
Frontier
Nov 13
STL2:12 pmLambert-St Louis
6h 10m
1 stop
PHL9:22 pmPhiladelphia
Nov 15
PHL6:50 pmPhiladelphia
19h 27m
1 stop
STL1:17 pmLambert-St Louis
$111
Find similar
Frontier
Dec 12
STL7:43 pmLambert-St Louis
8h 48m
1 stop
PHL5:31 amPhiladelphia
Jan 10
PHL8:00 pmPhiladelphia
27h 33m
1 stop
STL10:33 pmLambert-St Louis
$125
Find similar

American Airlines flights from St. Louis to Philadelphia

Our best American Airlines deals on St. Louis to Philadelphia flight tickets
American Airlines
Dec 10
STL6:00 amLambert-St Louis
2h 19m
PHL9:19 amPhiladelphia
Dec 10
PHL10:25 amPhiladelphia
6h 41m
1 stop
STL4:06 pmLambert-St Louis
$294
Find similar
American Airlines
Nov 13
STL6:00 amLambert-St Louis
2h 06m
PHL9:06 amPhiladelphia
Nov 17
PHL7:13 pmPhiladelphia
2h 47m
STL9:00 pmLambert-St Louis
$571
Find similar
American Airlines
Nov 1
STL5:20 amLambert-St Louis
8h 26m
1 stop
PHL2:46 pmPhiladelphia
Nov 5
PHL6:00 amPhiladelphia
8h 14m
1 stop
STL1:14 pmLambert-St Louis
$625
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 October 30, 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

Thu 11/13

2:12 pm-9:22 pm

1 stop6h 10m

Philadelphia

Mon 11/17

5:05 am-1:17 pm

1 stop9h 12m

$110

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Thu 11/13

2:12 pm-9:22 pm

1 stop6h 10m

Philadelphia

Sat 11/15

6:50 pm-1:17 pm

1 stop19h 27m

$111

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 12/12

7:43 pm-5:31 am

1 stop8h 48m

Philadelphia

Sat 1/10

8:00 pm-10:33 pm

1 stop27h 33m

$125

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 11/14

5:05 pm-1:24 am

1 stop7h 19m

Philadelphia

Mon 11/17

5:05 am-1:17 pm

1 stop9h 12m

$127

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 12/5

10:42 am-7:30 pm

1 stop7h 48m

Philadelphia

Sun 12/7

8:36 pm-10:14 am

1 stop14h 38m

$139

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Fri 11/14

4:56 pm-12:19 am

1 stop6h 23m

Philadelphia

Mon 11/17

5:05 am-1:17 pm

1 stop9h 12m

$143

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 12/3

3:30 pm-12:36 pm

1 stop20h 06m

Philadelphia

Fri 12/5

8:36 pm-10:14 am

1 stop14h 38m

$145

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 11/12

7:45 pm-4:49 am

1 stop8h 04m

Philadelphia

Sun 11/16

7:00 am-5:22 pm

1 stop11h 22m

$163

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 11/19

7:24 pm-3:04 pm

1 stop18h 40m

Philadelphia

Fri 11/21

8:54 pm-8:57 am

1 stop13h 03m

$165

St. LouisPhiladelphia

STL - PHL

STLPHL

Lambert-St Louis

Wed 12/10

6:00 am-9:19 am

Nonstop2h 19m

Philadelphia

Wed 12/10

10:25 am-4:06 pm

1 stop6h 41m

$294

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 typical price of a round-trip flight between St. Louis and Philadelphia?

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 $672. 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 $933.

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 $426. 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 $1,142.

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 $396 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 $310 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.

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

As of October 2025, prices for St. Louis to Philadelphia flights are approximately 166% more expensive 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

$221

Fastest flight time

2h 03m

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 $221. The best round-trip flight deal from St. Louis to Philadelphia found on momondo in the last 72 hours is $394.
The fastest flight from St. Louis to Philadelphia takes 2h 03m
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 19m, 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 $106Free CancellationRating
6.3
8,115 reviews
Search Spirit Airlines flights
FrontierPriceFrom $137Free CancellationRating
5.8
3,123 reviews
Search Frontier flights
American AirlinesPriceFrom $243Free CancellationRating
7.2
11,030 reviews
Search American Airlines flights
SouthwestPriceFrom $297Free CancellationRating
8.0
4,242 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 2 Southwest flights for this route in a normal week, average airfare is usually $421 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 11,030 reviews) operates around 3 flights from St. Louis to Philadelphia in any given week. The average American Airlines airfare for this route is around $418, with deals from around $243 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
Ocean City
Wildwood Crest
King of Prussia
Dewey Beach
Cherry Hill
Reading
Newark
North Wildwood
Dover
Avalon
Lewes
Stone Harbor
Vineland
Essington
Pottstown
New Castle
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

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