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Cheap flights from Philadelphia to St. Louis from $64

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 2/2. 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 Philadelphia to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
3:54 pm - 11:33 pm
PHL
-
STL
8h 39m1 stop
Frontier Logo
5:42 pm - 10:37 am
STL
-
PHL
15h 55m1 stop
$147Frontier
Mon, Feb 2 - Tue, Feb 3
Frontier Logo
9:02 pm - 10:23 am
PHL
-
STL
14h 21m1 stop
Frontier Logo
5:42 pm - 9:21 am
STL
-
PHL
14h 39m1 stop
$161Frontier
Thu, Jan 22 - Sun, Jan 25
Frontier Logo
3:56 pm - 10:33 pm
PHL
-
STL
7h 37m1 stop
Frontier Logo
5:11 pm - 12:29 am
STL
-
PHL
6h 18m1 stop
$162Frontier
Thu, Jan 8 - Mon, Jan 12
Frontier Logo
4:08 pm - 10:34 pm
PHL
-
STL
7h 26m1 stop
Frontier Logo
11:00 am - 10:46 pm
STL
-
PHL
10h 46m1 stop
$164Frontier
Sat, Jan 17 - Sat, Jan 24
Multiple Airlines Logo
8:43 pm - 10:23 am
PHL
-
STL
14h 40m1 stop
Multiple Airlines Logo
5:42 pm - 1:49 pm
STL
-
PHL
19h 07m2 stops
$165Multiple Airlines
Thu, Jan 22 - Sun, Jan 25
Frontier Logo
3:56 pm - 10:33 pm
PHL
-
STL
7h 37m1 stop
Frontier Logo
5:11 pm - 2:51 pm
STL
-
PHL
20h 40m1 stop
$169Frontier
Thu, Jan 8 - Sat, Jan 10
Multiple Airlines Logo
3:54 pm - 11:33 pm
PHL
-
STL
8h 39m1 stop
Multiple Airlines Logo
5:42 pm - 3:40 pm
STL
-
PHL
20h 58m2 stops
$170Multiple Airlines
Mon, Feb 2 - Tue, Feb 3
Frontier Logo
8:40 pm - 9:21 am
PHL
-
STL
13h 41m1 stop
Frontier Logo
5:42 pm - 11:14 am
STL
-
PHL
16h 32m2 stops
$182Frontier
Sun, Feb 1 - Mon, Feb 2
Multiple Airlines Logo
3:48 pm - 10:33 pm
PHL
-
STL
7h 45m1 stop
Multiple Airlines Logo
5:11 pm - 11:14 am
STL
-
PHL
41h 03m2 stops
$191Multiple Airlines
Wed, Jan 7 - Sun, Jan 11
Frontier Logo
5:10 am - 7:11 pm
PHL
-
STL
15h 01m1 stop
Frontier Logo
5:11 pm - 10:31 am
STL
-
PHL
16h 20m1 stop
$192Frontier
Sun, Feb 22 - Mon, Feb 23

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Feb 2
PHL3:54 pmPhiladelphia
8h 39m
1 stop
STL11:33 pmLambert-St Louis
Feb 3
STL5:42 pmLambert-St Louis
15h 55m
1 stop
PHL10:37 amPhiladelphia
$147
Find similar
Frontier
Jan 22
PHL9:02 pmPhiladelphia
14h 21m
1 stop
STL10:23 amLambert-St Louis
Jan 25
STL5:42 pmLambert-St Louis
14h 39m
1 stop
PHL9:21 amPhiladelphia
$161
Find similar
Frontier
Jan 8
PHL3:56 pmPhiladelphia
7h 37m
1 stop
STL10:33 pmLambert-St Louis
Jan 12
STL5:11 pmLambert-St Louis
6h 18m
1 stop
PHL12:29 amPhiladelphia
$162
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 December 8, 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 2/2

3:54 pm-11:33 pm

1 stop8h 39m

Lambert-St Louis

Tue 2/3

5:42 pm-10:37 am

1 stop15h 55m

$147

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 1/22

9:02 pm-10:23 am

1 stop14h 21m

Lambert-St Louis

Sun 1/25

5:42 pm-9:21 am

1 stop14h 39m

$161

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 1/8

3:56 pm-10:33 pm

1 stop7h 37m

Lambert-St Louis

Mon 1/12

5:11 pm-12:29 am

1 stop6h 18m

$162

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

$164

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 1/22

8:43 pm-10:23 am

1 stop14h 40m

Lambert-St Louis

Sun 1/25

5:42 pm-1:49 pm

2 stops19h 07m

$165

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 1/8

3:56 pm-10:33 pm

1 stop7h 37m

Lambert-St Louis

Sat 1/10

5:11 pm-2:51 pm

1 stop20h 40m

$169

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 2/2

3:54 pm-11:33 pm

1 stop8h 39m

Lambert-St Louis

Tue 2/3

5:42 pm-3:40 pm

2 stops20h 58m

$170

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 2/1

8:40 pm-9:21 am

1 stop13h 41m

Lambert-St Louis

Mon 2/2

5:42 pm-11:14 am

2 stops16h 32m

$182

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 1/7

3:48 pm-10:33 pm

1 stop7h 45m

Lambert-St Louis

Sun 1/11

5:11 pm-11:14 am

2 stops41h 03m

$191

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 2/22

5:10 am-7:11 pm

1 stop15h 01m

Lambert-St Louis

Mon 2/23

5:11 pm-10:31 am

1 stop16h 20m

$192

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, August 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 $320. The month of September 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 $385. 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 $464. 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 $380 when looking at flights departing in the afternoon. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $432 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 $321 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 December 2025, prices for Philadelphia to St. Louis flights are approximately 3% more expensive 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

$197

Fastest flight time

2h 25m

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 $197. The best round-trip flight deal from Philadelphia to St. Louis found on momondo in the last 72 hours is $372.
The fastest flight from Philadelphia to St. Louis takes 2h 25m
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 5h 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
8,168 reviews
Search Spirit Airlines flights
FrontierPriceFrom $130Free CancellationRating
5.8
3,085 reviews
Search Frontier flights
American AirlinesPriceFrom $241Free CancellationRating
7.2
11,045 reviews
Search American Airlines flights
SouthwestPriceFrom $257Free CancellationRating
8.0
4,254 reviews
Search Southwest flights
DeltaPriceFrom $259Free CancellationRating
7.9
8,011 reviews
Search Delta flights

  • Southwest Flights From Philadelphia to St. Louis

    The lowest priced Southwest flight from Philadelphia to St. Louis from the last 72 hours was $257. Generally, Southwest has 22 flights on this route every week with an average price of $419. 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 $418, however, with flight time and availability significantly affecting the price. American Airlines (7.2/10 from 11,045 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
Maryland Heights
O'Fallon
Florissant
Fenton
Wentzville
St. Peters
Collinsville
Alton
Farmington
Festus
Clayton
Glencoe
Edwardsville
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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