Latest deals
Insights
When to book
FAQs
Reviews
Price Alerts

Cheap flights from Philadelphia to St. Louis from $73

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 9/22. 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

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Price Alerts

Not ready to book? to track prices.
Search flight deals

Find the cheapest flights from Philadelphia to St. Louis

Cheap round-trip flights

Logo
9:50 pm - 9:40 amPHL-STL
12h 50m1 stop
Logo
7:55 pm - 12:57 amSTL-PHL
28h 02m1 stop
$199
Find Deal
Sat, Sep 20 - Wed, Sep 24
Spirit Airlines Logo
5:15 am - 11:01 amPHL-STL
6h 46m1 stop
Spirit Airlines Logo
12:20 pm - 12:32 amSTL-PHL
11h 12m1 stop
$200Spirit Airlines
Find Deal
Thu, Dec 11 - Sun, Dec 14
Frontier Logo
5:05 am - 1:17 pmPHL-STL
9h 12m1 stop
Frontier Logo
7:45 pm - 4:49 amSTL-PHL
8h 04m1 stop
$201Frontier
Find Deal
Fri, Nov 14 - Sun, Nov 16
Spirit Airlines Logo
5:25 am - 5:45 pmPHL-STL
13h 20m1 stop
Spirit Airlines Logo
10:57 am - 12:35 amSTL-PHL
12h 38m1 stop
$202Spirit Airlines
Find Deal
Sat, Oct 18 - Sun, Oct 26
Frontier Logo
6:40 pm - 1:02 pmPHL-STL
19h 22m1 stop
Frontier Logo
7:55 pm - 12:57 amSTL-PHL
28h 02m1 stop
$204Frontier
Find Deal
Thu, Sep 4 - Sat, Sep 6
Logo
12:00 pm - 9:40 amPHL-STL
22h 40m1 stop
Logo
4:00 pm - 12:57 amSTL-PHL
7h 57m1 stop
$205
Find Deal
Wed, Sep 10 - Thu, Sep 11
Frontier Logo
6:45 am - 9:06 amPHL-STL
27h 21m1 stop
Frontier Logo
4:00 pm - 9:32 pmSTL-PHL
28h 32m2 stops
$206Frontier
Find Deal
Fri, Sep 26 - Mon, Sep 29
Logo
12:43 pm - 1:02 pmPHL-STL
25h 19m1 stop
Logo
10:35 am - 12:17 amSTL-PHL
12h 42m1 stop
$209
Find Deal
Thu, Sep 4 - Sun, Sep 7
Logo
12:00 pm - 9:40 amPHL-STL
22h 40m1 stop
Logo
4:00 pm - 12:57 amSTL-PHL
7h 57m1 stop
$211
Find Deal
Wed, Sep 24 - Thu, Sep 25
Frontier Logo
5:15 am - 3:04 pmPHL-STL
10h 49m1 stop
Frontier Logo
4:00 pm - 10:56 amSTL-PHL
17h 56m1 stop
$215Frontier
Find Deal
Thu, Sep 4 - Sun, Sep 7

Frontier flights from Philadelphia to St. Louis

Our best Frontier deals on Philadelphia to St. Louis flight tickets
Frontier
Nov 14
PHL5:05 amPhiladelphia
9h 12m
1 stop
STL1:17 pmLambert-St Louis
Nov 16
STL7:45 pmLambert-St Louis
8h 04m
1 stop
PHL4:49 amPhiladelphia
$201
Find similar
Frontier
Sep 4
PHL6:40 pmPhiladelphia
19h 22m
1 stop
STL1:02 pmLambert-St Louis
Sep 6
STL7:55 pmLambert-St Louis
28h 02m
1 stop
PHL12:57 amPhiladelphia
$204
Find similar
Frontier
Sep 26
PHL6:45 amPhiladelphia
27h 21m
1 stop
STL9:06 amLambert-St Louis
Sep 29
STL4:00 pmLambert-St Louis
28h 32m
2 stops
PHL9:32 pmPhiladelphia
$206
Find similar

Spirit Airlines flights from Philadelphia to St. Louis

Our best Spirit Airlines deals on Philadelphia to St. Louis flight tickets
Spirit Airlines
Dec 11
PHL5:15 amPhiladelphia
6h 46m
1 stop
STL11:01 amLambert-St Louis
Dec 14
STL12:20 pmLambert-St Louis
11h 12m
1 stop
PHL12:32 amPhiladelphia
$200
Find similar
Spirit Airlines
Oct 18
PHL5:25 amPhiladelphia
13h 20m
1 stop
STL5:45 pmLambert-St Louis
Oct 26
STL10:57 amLambert-St Louis
12h 38m
1 stop
PHL12:35 amPhiladelphia
$202
Find similar
Spirit Airlines
Oct 17
PHL9:55 pmPhiladelphia
20h 50m
1 stop
STL5:45 pmLambert-St Louis
Oct 19
STL10:57 amLambert-St Louis
12h 38m
1 stop
PHL12:35 amPhiladelphia
$228
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 August 21, 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

Sat 9/20

9:50 pm-9:40 am

1 stop12h 50m

Lambert-St Louis

Wed 9/24

7:55 pm-12:57 am

1 stop28h 02m

$199

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 12/11

5:15 am-11:01 am

1 stop6h 46m

Lambert-St Louis

Sun 12/14

12:20 pm-12:32 am

1 stop11h 12m

$200

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 11/14

5:05 am-1:17 pm

1 stop9h 12m

Lambert-St Louis

Sun 11/16

7:45 pm-4:49 am

1 stop8h 04m

$201

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 10/18

5:25 am-5:45 pm

1 stop13h 20m

Lambert-St Louis

Sun 10/26

10:57 am-12:35 am

1 stop12h 38m

$202

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 9/4

6:40 pm-1:02 pm

1 stop19h 22m

Lambert-St Louis

Sat 9/6

7:55 pm-12:57 am

1 stop28h 02m

$204

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 9/10

12:00 pm-9:40 am

1 stop22h 40m

Lambert-St Louis

Thu 9/11

4:00 pm-12:57 am

1 stop7h 57m

$205

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 9/26

6:45 am-9:06 am

1 stop27h 21m

Lambert-St Louis

Mon 9/29

4:00 pm-9:32 pm

2 stops28h 32m

$206

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 9/4

12:43 pm-1:02 pm

1 stop25h 19m

Lambert-St Louis

Sun 9/7

10:35 am-12:17 am

1 stop12h 42m

$209

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 9/24

12:00 pm-9:40 am

1 stop22h 40m

Lambert-St Louis

Thu 9/25

4:00 pm-12:57 am

1 stop7h 57m

$211

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 9/4

5:15 am-3:04 pm

1 stop10h 49m

Lambert-St Louis

Sun 9/7

4:00 pm-10:56 am

1 stop17h 56m

$215

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
1
2

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 $316. The month of September is another great option to travel to St. Louis, with average flight prices from Philadelphia averaging around $338.

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 $389. 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 $465. 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 $389 when looking at flights departing in the afternoon. In the morning is when there is more demand to fly to St. Louis, so prices are often more expensive at around $424 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 $397 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 $338 on momondo.

What cabin class options are available on Philadelphia to Lambert-St Louis flights?

There are 3 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 August 2025, prices for Philadelphia to St. Louis flights are approximately 2% cheaper 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

$162

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 $162. The best round-trip flight deal from Philadelphia to St. Louis found on momondo in the last 72 hours is $251.
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 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 6h 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
FrontierPriceFrom $75Free CancellationRating
5.8
3,207 reviews
Search Frontier flights
Spirit AirlinesPriceFrom $95Free CancellationRating
6.3
8,035 reviews
Search Spirit Airlines flights
American AirlinesPriceFrom $239Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
DeltaPriceFrom $259Free CancellationRating
7.9
7,981 reviews
Search Delta flights
SouthwestPriceFrom $262Free CancellationRating
8.0
4,245 reviews
Search Southwest flights

  • Southwest Flights From Philadelphia to St. Louis

    The lowest priced Southwest flight from Philadelphia to St. Louis from the last 72 hours was $262. Generally, Southwest has 10 flights on this route every week with an average price of $417. 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 $419, however, with flight time and availability significantly affecting the price. American Airlines (7.2/10 from 10,000 user reviews) flies into St. Louis from Philadelphia 16 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
Fairview Heights
Hermann
Maryland Heights
Florissant
O'Fallon
Fenton
Collinsville
Wentzville
Alton
St. Peters
Festus
Farmington
Glencoe
Clayton
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

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.
Start using Trips
Find my bookings

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.
1 adult
Tue 8/26
Tue 9/2
By creating a price alert you accept our terms of use and privacy policy.

Find better results for your trip to the United States