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$90+ Cheap flights from Philadelphia to St. Louis (PHL - STL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/13. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Apr 15 — Apr 221
Wed 4/15
Wed 4/22
1 adult, Economy
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Cheapflights Tip: The best prices from Philadelphia to Lambert-St Louis are usually found in September or August, booked 58 days in advance, depart on a Wednesday or Saturday and return on a Thursday

Cheap flight deals from Philadelphia to St. Louis

Cheapest flights from Philadelphia to St. Louis
Explore the most affordable flight options available from Philadelphia to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 16, 2026.

This American Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/115:44 pm
PHL
-
STL
Nonstop2h 47m
American Airlines
Sat 5/166:29 am
STL
-
PHL
Nonstop2h 16m
American Airlines
Deal found 3/12$318
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/206:10 am
PHL
-
STL
Nonstop2h 25m
Southwest
Mon 4/201:35 pm
STL
-
PHL
Nonstop2h 10m
Southwest
Deal found 3/13$319
This Expedia deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 3/185:05 am
PHL
-
STL
1 stop6h 32m
Frontier
Thu 3/194:51 pm
STL
-
PHL
1 stop17h 50m
Frontier
Deal found 3/15$320
This Frontier deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/315:05 am
PHL
-
STL
1 stop6h 27m
Frontier
Sat 4/48:16 pm
STL
-
PHL
1 stop8h 18m
Frontier
Deal found 3/15$321
This Kiwi.com deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/88:35 pm
PHL
-
STL
2 stops13h 20m
Frontier
Sun 5/104:19 pm
STL
-
PHL
1 stop7h 21m
Frontier
Deal found 3/12$322
This Trip.com deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/315:05 am
PHL
-
STL
1 stop6h 27m
Frontier
Thu 4/24:54 pm
STL
-
PHL
1 stop13h 47m
Frontier
Deal found 3/14$323
This Kiwi.com deal was found by Cheapflights users on 3/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/215:45 am
PHL
-
STL
2 stops26h 05m
Multiple Airlines
Sun 4/264:59 pm
STL
-
PHL
1 stop14h 57m
Multiple Airlines
Deal found 3/16$324
This Frontier deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 3/138:25 pm
PHL
-
STL
1 stop14h 24m
Frontier
Fri 5/88:08 pm
STL
-
PHL
1 stop8h 29m
Frontier
Deal found 3/12$325
This Kiwi.com deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/225:45 am
PHL
-
STL
2 stops29h 45m
Multiple Airlines
Sun 4/264:59 pm
STL
-
PHL
1 stop14h 57m
Multiple Airlines
Deal found 3/14$326
This Kiwi.com deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/38:25 pm
PHL
-
STL
1 stop14h 23m
Multiple Airlines
Tue 4/711:21 am
STL
-
PHL
2 stops24h 43m
Multiple Airlines
Deal found 3/15$327
This American Airlines deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/97:40 pm
PHL
-
STL
1 stop5h 06m
American Airlines
Mon 4/131:29 pm
STL
-
PHL
Nonstop2h 20m
American Airlines
Deal found 3/14$328

Find flight deals from Philadelphia to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Philadelphia (PHL) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated March 16, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$318
(American Airlines)

One-way from

$90
(Frontier)

Popular in

May

Cheapest in

September

Average price

$401

Good round-trip deal

$345 or less

Good one-way deal

$168 or less
Provider with most accurate pricing for Philadelphia-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Philadelphia-Lambert-St Louis flights.
Search Deals
From Philadelphia to Lambert-St Louis
Search Deals
One-way flight from Philadelphia to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 7% potential increase in price ($32 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($8 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
Search Deals
Price to beat on a round-trip flight from Philadelphia to Lambert-St Louis.
Search Deals
Price to beat on a one-way flight from Philadelphia to Lambert-St Louis.
Search Deals

Cheapflights 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, Cheapflights users made 2,558,603 searches. Data last updated March 16, 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

Cheapest round-trip
Quickest round-trip

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 4/7

6:35 pm-8:00 pm

Nonstop2h 25m

Lambert-St Louis

Tue 4/14

1:40 pm-4:50 pm

Nonstop2h 10m

$319

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 5/28

7:10 pm-8:50 pm

Nonstop2h 40m

Lambert-St Louis

Tue 6/2

1:45 pm-9:05 pm

1 stop6h 20m

$329

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 4/9

2:15 pm-6:55 pm

1 stop5h 40m

Lambert-St Louis

Mon 4/13

7:55 pm-11:05 pm

Nonstop2h 10m

$329

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 4/27

6:35 pm-12:15 am

1 stop6h 40m

Lambert-St Louis

Fri 5/1

1:35 pm-4:45 pm

Nonstop2h 10m

$345

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 5/5

11:35 am-8:00 pm

2 stops9h 25m

Lambert-St Louis

Thu 5/7

9:55 am-6:25 pm

2 stops7h 30m

$354

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 4/16

2:15 pm-11:15 pm

2 stops10h 00m

Lambert-St Louis

Sat 4/18

5:40 am-3:45 pm

2 stops9h 05m

$365

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 5/8

6:10 am-7:35 am

Nonstop2h 25m

Lambert-St Louis

Tue 5/12

6:50 pm-10:00 pm

Nonstop2h 10m

$391

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 5/16

7:45 am-4:20 pm

2 stops9h 35m

Lambert-St Louis

Mon 5/18

1:45 pm-10:45 pm

2 stops8h 00m

$421

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 4/22

5:50 am-1:00 pm

2 stops8h 10m

Lambert-St Louis

Fri 4/24

9:55 am-6:25 pm

2 stops7h 30m

$421

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 8/1

1:45 pm-3:05 pm

Nonstop2h 20m

Lambert-St Louis

Tue 8/4

4:05 pm-11:50 pm

1 stop6h 45m

$473

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/11

Showing 1-10 of 22 resultsSorted by cheapest first
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Compare providers for flights from Philadelphia to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Philadelphia to St. Louis in March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
PricelinePrice Accuracy1 starTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Philadelphia-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Philadelphia-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Philadelphia-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Philadelphia-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Philadelphia-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Philadelphia to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Philadelphia with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Philadelphia to St. Louis

How far ahead should I book a flight from Philadelphia to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Philadelphia to St. Louis. Price data was last updated on March 13, 2026.

Booking 58 days in advance of your planned departure date is, on average, the best time to get cheap flights from Philadelphia to St. Louis. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Philadelphia to St. Louis?

Currently, March is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $109). Flying from Philadelphia to St. Louis in February is currently the most expensive (average of $241). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from PHL to STL?

Find hourly flight availability from Philadelphia to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated March 16, 2026.

It’s optimal to fly from Philadelphia to St. Louis in the afternoon. By choosing this option you can save up to 11% on the cost of your flight, compared to a flight at noon.

What is the cheapest day to fly from Philadelphia to St. Louis?

Use this chart to determine the cheapest time to fly round-trip from Philadelphia to St. Louis. Price data was last updated on March 14, 2026.

Travelers seeking maximum savings on their Philadelphia to St. Louis flight should consider departing on Tuesday afternoons when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

The best insider tips for Philadelphia to St. Louis flights

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Philadelphia to St. Louis trip
Our travel experts
Mark Chesnut

Mark Chesnut

Expert on PHL

Mark Chesnut is a travel writer and public speaker with more than 30 years of experience. The 2019 winner of the NLGJA Excellence in Travel Writing Award, Mark is the author of the book “Prepare for Departure” and has covered air travel for multiple top consumer and trade media outlets.

Read more
Taryn White

Taryn White

Expert on STL

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Read more

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to St. Louis. Reviews last updated March 16, 2026.
See what other customers who have flown with Southwest,Delta, andAmerican Airlines from Philadelphia to St. Louis have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Southwest
8.0
Very good
4,318 reviews
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Delta
7.9
Good
8,296 reviews
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
American Airlines
7.1
Good
11,466 reviews
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Spirit Airlines
6.3
Okay
8,520 reviews
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Frontier
5.7
Fair
3,030 reviews
Southwest
8.0
Very good
4,318 reviews

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..

Related info for your journey

Find useful and relevant information for your journey from Philadelphia to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airports do I use to fly from Philadelphia to St. Louis?

    Lambert-St Louis is the airport most travelers will use when flying to St. Louis from Philadelphia. Booking flights from Philadelphia (PHL) to Lambert-St Louis (STL) should be relatively easy as there are 7 daily flights to St. Louis from 5 different airlines. 2h 15m is how long a flight from Philadelphia to Lambert-St Louis will take if you book a nonstop flight.

  • How popular is this Philadelphia to St. Louis flight route?

    This flight path from Philadelphia to Lambert-St Louis was viewed by 32 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • How long is the flight from Philadelphia to St. Louis?

    Airlines like Southwest fly from Philadelphia to St. Louis in about 2h 25m. The time it takes to get you to your destination is usually consistent. The distance between Philadelphia and St. Louis is about 811 mi. All flights are typically nonstop.

  • What are the cheapest airlines flying from Philadelphia to St. Louis round-trip?

    Cheapflights users have booked flights from Philadelphia to St. Louis round-trip from $93. Other airlines that can offer you cheap pricing are Frontier, from $135, and American Airlines, from $237. These flights start at 76% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from Philadelphia to St. Louis one-way?

    The cheapest airline one-way is Frontier, with whom users have recently found tickets for as low as $70. However, be on the lookout for offers from Spirit Airlines and American Airlines, as they are both options that can get you from Philadelphia to St. Louis for a low price.

  • What are the most reliable airlines from Philadelphia to St. Louis?

    Consider Aer Lingus (86%), Republic Airways (83%) or Southwest (82%) when booking your flight. These represent the most reliable airlines when flying from Philadelphia to St. Louis.

  • What are the cheapest flights from Philadelphia to St. Louis?

    Looking for the cheapest flight from Philadelphia to St. Louis? While on average our users pay $315, our data indicates the cheapest price to be $97. The most popular route (Philadelphia - Lambert-St Louis), is priced around $234.

  • Can I find deals for flights from Philadelphia to St. Louis that include hotel bookings?

    Yes. In addition to deals on Philadelphia to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Philadelphia to St. Louis?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Philadelphia to St. Louis.

  • Can I find deals for business class flights from Philadelphia to St. Louis?

    Yes. Cheapflights offers flight deals from Philadelphia to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Philadelphia to St. Louis?

    Currently, March is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $109). Flying from Philadelphia to St. Louis in February is currently the most expensive (average of $241). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fenton
Swansea
Fairview Heights
Maryland Heights
Collinsville
Eureka
Wentzville
Glencoe
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

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Top 5 airlines flying from Philadelphia to St. Louis

Discover the top 5 airlines that operate flights from Philadelphia to St. Louis. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 16, 2026.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$93Average$178FlexibilityNo cancel feeOn-time65%
FrontierCheapest$135Average$230FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$237Average$412FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$251Average$416FlexibilityNo cancel feeOn-time63%
DeltaCheapest$297Average$425FlexibilityNo cancel feeOn-timeN/A

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