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Cheap flights from Philadelphia to St. Louis 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 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.
Multiple Airlines Logo
5:26 pm - 6:51 am
PHL
-
STL
14h 25m
2 stops
Multiple Airlines Logo
3:49 pm - 2:40 pm
STL
-
PHL
21h 51m
1 stop
$145Multiple Airlines
Tue, Feb 17 - Tue, Feb 24
Frontier Logo
5:30 am - 6:51 am
PHL
-
STL
26h 21m
1 stop
Frontier Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
$147Frontier
Thu, Feb 26 - Tue, Mar 3
Frontier Logo
5:30 am - 6:51 am
PHL
-
STL
26h 21m
1 stop
Frontier Logo
3:49 pm - 12:39 pm
STL
-
PHL
19h 50m
1 stop
$149Frontier
Thu, Feb 26 - Mon, Mar 2
Frontier Logo
7:10 pm - 6:51 am
PHL
-
STL
12h 41m
1 stop
Frontier Logo
3:49 pm - 12:22 pm
STL
-
PHL
19h 33m
1 stop
$152Frontier
Tue, Feb 17 - Tue, Feb 24
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
$158Frontier
Thu, Feb 26 - Wed, Mar 4
Frontier Logo
5:42 pm - 1:09 pm
PHL
-
STL
20h 27m
1 stop
Frontier Logo
9:41 am - 7:49 pm
STL
-
PHL
9h 08m
1 stop
$160Frontier
Thu, Feb 19 - Sat, Feb 21
Frontier Logo
3:45 pm - 10:27 pm
PHL
-
STL
7h 42m
1 stop
Frontier Logo
8:12 pm - 7:07 am
STL
-
PHL
33h 55m
2 stops
$165Frontier
Wed, Mar 4 - Sat, Mar 7
Multiple Airlines Logo
7:46 pm - 11:59 pm
PHL
-
STL
29h 13m
1 stop
Multiple Airlines Logo
11:32 am - 12:52 am
STL
-
PHL
12h 20m
1 stop
$166Multiple Airlines
Wed, Mar 4 - Wed, Mar 11
Frontier Logo
8:25 pm - 7:12 pm
PHL
-
STL
23h 47m
1 stop
Frontier Logo
4:55 pm - 6:38 pm
STL
-
PHL
24h 43m
1 stop
$171Frontier
Wed, Apr 29 - Tue, May 5
Multiple Airlines Logo
5:26 pm - 6:51 am
PHL
-
STL
14h 25m
2 stops
Multiple Airlines Logo
3:49 pm - 2:44 pm
STL
-
PHL
21h 55m
1 stop
$172Multiple Airlines
Fri, Feb 20 - Mon, Feb 23

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Feb 26
PHL5:30 amPhiladelphia
26h 21m
1 stop
STL6:51 amLambert-St Louis
Mar 3
STL3:49 pmLambert-St Louis
19h 33m
1 stop
PHL12:22 pmPhiladelphia
$147
Frontier
Feb 26
PHL5:30 amPhiladelphia
26h 21m
1 stop
STL6:51 amLambert-St Louis
Mar 2
STL3:49 pmLambert-St Louis
19h 50m
1 stop
PHL12:39 pmPhiladelphia
$149
Frontier
Feb 17
PHL7:10 pmPhiladelphia
12h 41m
1 stop
STL6:51 amLambert-St Louis
Feb 24
STL3:49 pmLambert-St Louis
19h 33m
1 stop
PHL12:22 pmPhiladelphia
$152

United Airlines flights from Philadelphia to St. Louis

Our best United Airlines deals on Philadelphia to St. Louis flight tickets
United Airlines
Feb 10
PHL1:10 pmPhiladelphia
5h 33m
1 stop
STL5:43 pmLambert-St Louis
Feb 12
STL6:30 amLambert-St Louis
6h 49m
1 stop
PHL2:19 pmPhiladelphia
$732
United Airlines
Feb 12
PHL5:00 pmPhiladelphia
6h 59m
1 stop
STL10:59 pmLambert-St Louis
Feb 16
STL7:41 amLambert-St Louis
25h 07m
2 stops
PHL9:48 amPhiladelphia
$757
United Airlines
Feb 14
PHL10:35 amPhiladelphia
11h 30m
2 stops
STL9:05 pmLambert-St Louis
Feb 16
STL7:41 amLambert-St Louis
5h 38m
1 stop
PHL2:19 pmPhiladelphia
$796

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 February 5, 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

Tue 2/17

5:26 pm-6:51 am

2 stops14h 25m

Lambert-St Louis

Tue 2/24

3:49 pm-2:40 pm

1 stop21h 51m

$145

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 2/26

5:30 am-6:51 am

1 stop26h 21m

Lambert-St Louis

Tue 3/3

3:49 pm-12:22 pm

1 stop19h 33m

$147

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 2/26

5:30 am-6:51 am

1 stop26h 21m

Lambert-St Louis

Mon 3/2

3:49 pm-12:39 pm

1 stop19h 50m

$149

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 2/17

7:10 pm-6:51 am

1 stop12h 41m

Lambert-St Louis

Tue 2/24

3:49 pm-12:22 pm

1 stop19h 33m

$152

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

$158

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 2/19

5:42 pm-1:09 pm

1 stop20h 27m

Lambert-St Louis

Sat 2/21

9:41 am-7:49 pm

1 stop9h 08m

$160

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 3/4

3:45 pm-10:27 pm

1 stop7h 42m

Lambert-St Louis

Sat 3/7

8:12 pm-7:07 am

2 stops33h 55m

$165

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 3/4

7:46 pm-11:59 pm

1 stop29h 13m

Lambert-St Louis

Wed 3/11

11:32 am-12:52 am

1 stop12h 20m

$166

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 4/29

8:25 pm-7:12 pm

1 stop23h 47m

Lambert-St Louis

Tue 5/5

4:55 pm-6:38 pm

1 stop24h 43m

$171

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 2/20

5:26 pm-6:51 am

2 stops14h 25m

Lambert-St Louis

Mon 2/23

3:49 pm-2:44 pm

1 stop21h 55m

$172

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 $466. 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 $382 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 $439 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 February 2026, prices for Philadelphia to St. Louis flights are approximately 61% 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

$189

Fastest flight time

2h 15m

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 $189. The best round-trip flight deal from Philadelphia to St. Louis found on momondo in the last 72 hours is $388.
The fastest flight from Philadelphia to St. Louis takes 2h 15m
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 15m 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
8,419 reviews
Search Spirit Airlines flights
FrontierPriceFrom $127Free CancellationRating
5.7
3,052 reviews
Search Frontier flights
American AirlinesPriceFrom $239Free CancellationRating
7.2
11,237 reviews
Search American Airlines flights
SouthwestPriceFrom $253Free CancellationRating
8.0
4,275 reviews
Search Southwest flights
DeltaPriceFrom $259Free CancellationRating
7.9
8,151 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 6 flights on this route every week with an average price of $420. Southwest is rated 8.0/10 by our users.

  • American Airlines Flights From Philadelphia to St. Louis

    $239 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 $415, however, with flight time and availability significantly affecting the price. American Airlines (7.2/10 from 11,237 user reviews) flies into St. Louis from Philadelphia 12 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
St. Peters
Fenton
Wentzville
Alton
Farmington
Clayton
Edwardsville
Eureka
Festus
Litchfield
Glencoe
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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