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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 3/3. 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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Find the cheapest flights from Philadelphia to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
Frontier Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
$134Frontier
Fri, Feb 27 - Tue, Mar 3
Frontier Logo
4:29 pm - 11:59 pm
PHL
-
STL
8h 30m
1 stop
Frontier Logo
3:49 pm - 9:53 pm
STL
-
PHL
29h 04m
1 stop
$138Frontier
Mon, Feb 23 - Wed, Feb 25
Frontier Logo
5:30 am - 6:51 am
PHL
-
STL
26h 21m
1 stop
Frontier Logo
8:17 pm - 10:27 am
STL
-
PHL
13h 10m
1 stop
$146Frontier
Thu, Feb 26 - Wed, Mar 4
Frontier Logo
4:14 pm - 10:27 pm
PHL
-
STL
7h 13m
1 stop
Frontier Logo
1:09 pm - 12:52 am
STL
-
PHL
10h 43m
1 stop
$155Frontier
Tue, Mar 3 - Fri, Mar 6
Frontier Logo
5:05 am - 10:30 am
PHL
-
STL
6h 25m
1 stop
Frontier Logo
8:13 pm - 8:10 am
STL
-
PHL
10h 57m
1 stop
$160Frontier
Thu, Apr 30 - Sat, May 2
Multiple Airlines Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
Multiple Airlines Logo
3:49 pm - 3:57 pm
STL
-
PHL
23h 08m
2 stops
$161Multiple Airlines
Fri, Feb 27 - Tue, Mar 3
Frontier Logo
7:12 pm - 6:51 am
PHL
-
STL
12h 39m
1 stop
Frontier Logo
8:17 pm - 11:18 am
STL
-
PHL
14h 01m
1 stop
$163Frontier
Sun, Feb 22 - Wed, Feb 25
Multiple Airlines Logo
8:06 am - 10:27 pm
PHL
-
STL
15h 21m
2 stops
Multiple Airlines Logo
1:09 pm - 12:52 am
STL
-
PHL
10h 43m
1 stop
$167Multiple Airlines
Tue, Mar 3 - Fri, Mar 6
Frontier Logo
4:14 pm - 10:27 pm
PHL
-
STL
7h 13m
1 stop
Frontier Logo
8:12 pm - 7:07 am
STL
-
PHL
33h 55m
2 stops
$169Frontier
Tue, Mar 3 - Sat, Mar 7
Frontier Logo
12:33 pm - 11:59 pm
PHL
-
STL
12h 26m
1 stop
Frontier Logo
3:49 pm - 12:39 pm
STL
-
PHL
19h 50m
1 stop
$175Frontier
Sat, Feb 21 - Mon, Feb 23

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Feb 23
PHL4:29 pmPhiladelphia
8h 30m
1 stop
STL11:59 pmLambert-St Louis
Feb 25
STL3:49 pmLambert-St Louis
29h 04m
1 stop
PHL9:53 pmPhiladelphia
$138
Frontier
Feb 5
PHL7:04 pmPhiladelphia
12h 47m
1 stop
STL6:51 amLambert-St Louis
Feb 6
STL8:22 pmLambert-St Louis
13h 56m
1 stop
PHL11:18 amPhiladelphia
$151
Frontier
Mar 3
PHL4:14 pmPhiladelphia
7h 13m
1 stop
STL10:27 pmLambert-St Louis
Mar 6
STL1:09 pmLambert-St Louis
10h 43m
1 stop
PHL12:52 amPhiladelphia
$155

Southwest flights from Philadelphia to St. Louis

Our best Southwest deals on Philadelphia to St. Louis flight tickets
Southwest
Feb 10
PHL12:15 pmPhiladelphia
7h 45m
2 stops
STL7:00 pmLambert-St Louis
Feb 13
STL3:10 pmLambert-St Louis
7h 40m
2 stops
PHL11:50 pmPhiladelphia
$601
Southwest
Feb 8
PHL2:10 pmPhiladelphia
2h 40m
STL3:50 pmLambert-St Louis
Feb 10
STL8:20 amLambert-St Louis
2h 10m
PHL11:30 amPhiladelphia
$694
Southwest
Feb 8
PHL2:10 pmPhiladelphia
2h 40m
STL3:50 pmLambert-St Louis
Feb 10
STL8:15 amLambert-St Louis
3h 55m
1 stop
PHL1:10 pmPhiladelphia
$704

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 January 29, 2026.
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

Fri 2/27

7:12 pm-6:51 am

1 stop12h 39m

Lambert-St Louis

Tue 3/3

3:49 pm-12:22 pm

1 stop19h 33m

$134

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 2/23

4:29 pm-11:59 pm

1 stop8h 30m

Lambert-St Louis

Wed 2/25

3:49 pm-9:53 pm

1 stop29h 04m

$138

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 2/26

5:30 am-6:51 am

1 stop26h 21m

Lambert-St Louis

Wed 3/4

8:17 pm-10:27 am

1 stop13h 10m

$146

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 3/3

4:14 pm-10:27 pm

1 stop7h 13m

Lambert-St Louis

Fri 3/6

1:09 pm-12:52 am

1 stop10h 43m

$155

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 4/30

5:05 am-10:30 am

1 stop6h 25m

Lambert-St Louis

Sat 5/2

8:13 pm-8:10 am

1 stop10h 57m

$160

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 2/27

7:12 pm-6:51 am

1 stop12h 39m

Lambert-St Louis

Tue 3/3

3:49 pm-3:57 pm

2 stops23h 08m

$161

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 2/22

7:12 pm-6:51 am

1 stop12h 39m

Lambert-St Louis

Wed 2/25

8:17 pm-11:18 am

1 stop14h 01m

$163

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 3/3

8:06 am-10:27 pm

2 stops15h 21m

Lambert-St Louis

Fri 3/6

1:09 pm-12:52 am

1 stop10h 43m

$167

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 3/3

4:14 pm-10:27 pm

1 stop7h 13m

Lambert-St Louis

Sat 3/7

8:12 pm-7:07 am

2 stops33h 55m

$169

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 2/21

12:33 pm-11:59 pm

1 stop12h 26m

Lambert-St Louis

Mon 2/23

3:49 pm-12:39 pm

1 stop19h 50m

$175

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

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 $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 $467. 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 $438 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 $404 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 $314 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.

Can stopping save me money on Philadelphia to St. Louis flights?

No. A direct flight is the cheapest option for a flight between Philadelphia to St. Louis.

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

As of January 2026, prices for Philadelphia to St. Louis flights are approximately 82% 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

$221

Fastest flight time

2h 20m

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 $221. The best round-trip flight deal from Philadelphia to St. Louis found on momondo in the last 72 hours is $401.
The fastest flight from Philadelphia to St. Louis takes 2h 20m
Direct flights go from Philadelphia to St. Louis every day.
There is 1 airport in St. Louis. From Philadelphia there are direct flights to 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 20m 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
8,393 reviews
Search Spirit Airlines flights
FrontierPriceFrom $127Free CancellationRating
5.7
3,056 reviews
Search Frontier flights
American AirlinesPriceFrom $241Free CancellationRating
7.2
11,205 reviews
Search American Airlines flights
SouthwestPriceFrom $253Free CancellationRating
8.0
4,267 reviews
Search Southwest flights
DeltaPriceFrom $259Free CancellationRating
7.9
8,128 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 $253. Generally, Southwest has 5 flights on this route every week with an average price of $421. 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 11,205 user reviews) flies into St. Louis from Philadelphia 6 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
Florissant
O'Fallon
Collinsville
Fenton
St. Peters
Wentzville
Alton
Farmington
Clayton
Edwardsville
Eureka
Festus
Glencoe
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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