$43+ Cheap flights from St. Louis to Philadelphia (STL - PHL)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/7. Fares are subject to change and may not be available on all flights or dates of travel.
STL — PHL
Oct 17 — Oct 241
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Philadelphia with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Lambert-St Louis to Philadelphia are usually found in September or October, booked 85 days in advance, depart on a Friday or Thursday and return on a Wednesday
Cheap flight deals from St. Louis to Philadelphia
Cheapest
Best
Last-minute
One-way
Cheapest flights from St. Louis to PhiladelphiaExplore the most affordable flight options available from St. Louis to Philadelphia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 17, 2026.
Explore the most affordable flight options available from St. Louis to Philadelphia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 17, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/14. 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 10/72:29 pm -
1 stop7h 49m
Wed 10/148:30 am -
1 stop10h 10m
Deal found 9/14![Frontier logo]()
$83
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 10/146:35 pm -
1 stop11h 36m
Wed 10/2112:35 pm -
1 stop6h 05m
Deal found 9/12![Frontier logo]()
$87
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 10/146:35 pm -
1 stop11h 36m
Tue 10/205:22 pm -
1 stop25h 18m
Deal found 9/12![Frontier logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 9/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/166:35 pm -
1 stop11h 46m
Tue 10/205:22 pm -
1 stop25h 18m
Deal found 9/13![Frontier logo]()
$96
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 11/46:44 pm -
1 stop11h 27m
Wed 11/1112:36 pm -
1 stop6h 04m
Deal found 9/12![Frontier logo]()
$114
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
1 stop11h 36m
Wed 10/2812:36 pm -
1 stop6h 04m
Deal found 9/16![Frontier logo]()
$118
This Kiwi.com deal was found by Cheapflights users on 9/14. 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 10/146:35 pm -
1 stop11h 36m
Thu 10/156:03 pm -
1 stop24h 37m
Deal found 9/14![Frontier logo]()
$138
This Super.com deal was found by Cheapflights users on 9/15. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
1 stop11h 36m
Mon 10/2612:35 pm -
1 stop6h 05m
Deal found 9/15![Frontier logo]()
$141
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Fri 11/66:44 pm -
1 stop11h 37m
Tue 11/105:22 pm -
1 stop25h 18m
Deal found 9/16![Frontier logo]()
$145
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Mon 10/126:35 pm -
1 stop11h 46m
Wed 10/148:30 am -
1 stop10h 10m
Deal found 9/16![Frontier logo]()
$148
Best flights from St. Louis to PhiladelphiaDiscover carefully curated flight deals from St. Louis to Philadelphia that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 17, 2026.
Discover carefully curated flight deals from St. Louis to Philadelphia that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 17, 2026.
This Southwest deal was found by Cheapflights users on 9/14. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/97:50 pm -
Nonstop2h 25m
Mon 10/126:25 am -
Nonstop2h 20m
Deal found 9/14![Southwest logo]()
$350
This Delta deal was found by Cheapflights users on 9/16. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/2910:05 am -
1 stop5h 08m
Tue 10/612:32 pm -
1 stop5h 47m
Deal found 9/16![Delta logo]()
$473
This United Airlines deal was found by Cheapflights users on 9/14. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/121:29 pm -
1 stop7h 00m
Tue 10/135:08 pm -
1 stop5h 13m
Deal found 9/14![United Airlines logo]()
$479
This Southwest deal was found by Cheapflights users on 9/13. 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.
Fri 10/167:50 pm -
Nonstop2h 25m
Mon 10/196:25 am -
Nonstop2h 20m
Deal found 9/13![Southwest logo]()
$350
This Southwest deal was found by Cheapflights users on 9/14. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/2411:55 am -
1 stop8h 05m
Mon 10/261:55 pm -
2 stops7h 00m
Deal found 9/14![Southwest logo]()
$364
This Southwest deal was found by Cheapflights users on 9/13. 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.
Tue 11/106:20 am -
1 stop6h 55m
Sun 11/156:00 am -
Nonstop2h 40m
Deal found 9/13![Southwest logo]()
$407
This Southwest deal was found by Cheapflights users on 9/16. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/238:10 pm -
Nonstop2h 10m
Sat 11/285:00 am -
Nonstop2h 30m
Deal found 9/16![Southwest logo]()
$458
This Southwest deal was found by Cheapflights users on 9/15. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/2910:55 am -
Nonstop2h 10m
Tue 10/66:00 am -
1 stop5h 20m
Deal found 9/15![Southwest logo]()
$480
Last-minute flights from St. Louis to PhiladelphiaDiscover last-minute flight deals from St. Louis to Philadelphia. Data last updated September 17, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Philadelphia. Data last updated September 17, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 9/14. 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 10/72:29 pm -
1 stop7h 49m
Wed 10/148:30 am -
1 stop10h 10m
Deal found 9/14![Frontier logo]()
$83
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Mon 10/126:35 pm -
1 stop11h 46m
Wed 10/148:30 am -
1 stop10h 10m
Deal found 9/16![Frontier logo]()
$148
This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
Mon 10/126:35 pm -
1 stop27h 36m
Mon 10/195:45 pm -
2 stops48h 55m
Deal found 9/14![Frontier logo]()
$150
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 10/146:35 pm -
1 stop11h 36m
Wed 10/2112:35 pm -
1 stop6h 05m
Deal found 9/12![Frontier logo]()
$87
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 10/146:35 pm -
1 stop11h 36m
Tue 10/205:22 pm -
1 stop25h 18m
Deal found 9/12![Frontier logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 9/14. 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 10/146:35 pm -
1 stop11h 36m
Thu 10/156:03 pm -
1 stop24h 37m
Deal found 9/14![Frontier logo]()
$138
This Kiwi.com deal was found by Cheapflights users on 9/14. 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 10/146:35 pm -
1 stop11h 36m
Mon 10/195:45 pm -
2 stops48h 55m
Deal found 9/14![Frontier logo]()
$149
This Kiwi.com deal was found by Cheapflights users on 9/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/166:35 pm -
1 stop11h 46m
Tue 10/205:22 pm -
1 stop25h 18m
Deal found 9/13![Frontier logo]()
$96
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
1 stop11h 36m
Wed 10/2812:36 pm -
1 stop6h 04m
Deal found 9/16![Frontier logo]()
$118
This Super.com deal was found by Cheapflights users on 9/15. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
1 stop11h 36m
Mon 10/2612:35 pm -
1 stop6h 05m
Deal found 9/15![Frontier logo]()
$141
One-way flights from St. Louis to PhiladelphiaSearch for one-way flight options from St. Louis to Philadelphia. Find affordable one-way fares based on user searches. Data last updated September 17, 2026.
Search for one-way flight options from St. Louis to Philadelphia. Find affordable one-way fares based on user searches. Data last updated September 17, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 10/72:29 pm -
1 stop7h 49m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$43
This Kiwi.com deal was found by Cheapflights users on 9/15. 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.
Wed 10/146:35 pm -
1 stop11h 36m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$48
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Fri 10/166:35 pm -
1 stop11h 46m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/16![Frontier logo]()
$54
This Kiwi.com deal was found by Cheapflights users on 9/15. 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 11/136:44 pm -
1 stop11h 37m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$55
This Kiwi.com deal was found by Cheapflights users on 9/15. 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.
Wed 11/116:44 pm -
1 stop11h 27m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$69
This Kiwi.com deal was found by Cheapflights users on 9/12. 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 10/96:35 pm -
1 stop27h 36m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$71
This Super.com deal was found by Cheapflights users on 9/13. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/126:35 pm -
1 stop11h 46m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$87
This Kiwi.com deal was found by Cheapflights users on 9/12. 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.
Wed 12/92:59 pm -
1 stop21h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$93
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Wed 12/1612:02 pm -
1 stop24h 13m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/16![Frontier logo]()
$94
Find flight deals from St. Louis to Philadelphia
Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Philadelphia (PHL). 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 September 17, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $83 (Kiwi.com) |
One-way from | $43 (Kiwi.com) |
Popular in | November |
Cheapest in | September |
Average price | $347 |
Good round-trip deal | $366 or less |
Good one-way deal | $186 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from St. Louis to Philadelphia 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 7,457,451 searches. Data last updated September 17, 2026.
Use the filters below to find and compare flights from St. Louis to Philadelphia that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Tue 10/13
12:10 pm-3:25 pm
Nonstop2h 15m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$150
Quickest round-trip
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Fri 11/13
8:10 pm-11:20 pm
Nonstop2h 10m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$167
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Fri 9/25
5:19 pm-12:09 am
1 stop5h 50m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$180
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Thu 11/12
5:30 pm-12:54 am
1 stop6h 24m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$182
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Tue 11/10
6:40 am-11:35 am
1 stop3h 55m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$194
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Fri 11/13
2:31 pm-10:13 pm
1 stop6h 42m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$194
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Tue 10/13
10:14 am-6:18 pm
1 stop7h 04m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$194
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Mon 11/30
6:35 pm-9:30 am
2 stops13h 55m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$212
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Sat 11/21
7:55 pm-11:05 pm
Nonstop2h 10m
Philadelphia
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$240
St. LouisPhiladelphia
STL Lambert-St Louis - PHL Philadelphia
STLPHL
Lambert-St Louis
Fri 10/9
7:50 pm-11:15 pm
Nonstop2h 25m
Philadelphia
Mon 10/12
6:25 am-7:45 am
Nonstop2h 20m
$350
Showing 1-10 of 17 resultsSorted by cheapest first
Compare providers for flights from St. Louis to Philadelphia
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 St. Louis to Philadelphia in September.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy2 stars | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on St. Louis-Philadelphia flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Philadelphia flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Philadelphia flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on St. Louis-Philadelphia 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 St. Louis-Philadelphia 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 St. Louis to Philadelphia
Have a flexible travel schedule? Discover the best time to fly to Philadelphia from St. Louis with our price prediction graph.
STL-PHL
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 St. Louis to Philadelphia
Prices
Airlines
More
How far ahead should I book a flight from St. Louis to Philadelphia?
The price you pay for your flight from St. Louis to Philadelphia may vary depending on when you book. For the best chance of a lower fare, look to book 90 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest month to book a flight from St. Louis to Philadelphia?
Currently, September is the cheapest month in which you can book a flight from St. Louis to Philadelphia (average of $347). Flying from St. Louis to Philadelphia in November is currently the most expensive (average of $515). 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 STL to PHL?
Find hourly flight availability from St. Louis to Philadelphia. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 17, 2026.
It’s typically best to fly out from St. Louis to Philadelphia in the evening. Doing so could potentially save you 46% on the flight price compared to flying at noon, which is usually more expensive.
What is the cheapest day to fly from St. Louis to Philadelphia?
Use this chart to determine the cheapest time to fly round-trip from St. Louis to Philadelphia. Price data was last updated on September 12, 2026.
Travelers seeking maximum savings on their St. Louis to Philadelphia flight should consider departing on Thursday evenings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
What’s the top layover airport for flights from St. Louis to Philadelphia?
Share of 1-stop round-trip flights from St. Louis to Philadelphia chosen by Cheapflights users in the past 12 months, using the same layover each way.
Orlando (MCO) – chosen by Cheapflights users on 67% of 1-stop itineraries from St. Louis to Philadelphia on Cheapflights.
What’s the cheapest layover airport for flights from St. Louis to Philadelphia?
Average round-trip fare for 1-stop flights from St. Louis to Philadelphia, chosen by Cheapflights users in the past 12 months, with the same layover each way.
Atlanta (ATL) is the most affordable 1-stop option, with an average round-trip price of $154.
What’s the fastest layover option from St. Louis to Philadelphia?
Shortest average travel time for 1-stop one-way flights from St. Louis to Philadelphia, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.
Flights via Orlando (MCO) have the shortest average one-way travel time for 1-stop routes: 6h 14m.
Which airport typically offers the quickest layover for flights from St. Louis to Philadelphia?
Average layover duration for 1-stop one-way flights from St. Louis to Philadelphia, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.
Flights via Orlando (MCO) offer the fastest connection on this route, with an average layover time of 2h 19m.
The best insider tips for St. Louis to Philadelphia 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 St. Louis to Philadelphia trip
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Reviews of airlines servicing Philadelphia
Get insights into the airlines that provide service to Philadelphia. 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 Philadelphia. Reviews last updated September 17, 2026.
Read reviews from past customers who have flown Southwest,American Airlines, andFrontier from St. Louis to Philadelphia. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Food
7.0
Overall
8.0
Boarding
8.1
Crew
8.6
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
4.0
OkaySteven,Sep 2026
OGG - HNL
Food
7.0
Overall
8.0
Boarding
8.1
Crew
8.6
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
4.0
OkaySteven,Sep 2026
OGG - HNL
Food
7.0
Overall
8.0
Boarding
8.1
Crew
8.6
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
4.0
OkaySteven,Sep 2026
OGG - HNL
Food
7.0
Overall
8.0
Boarding
8.1
Crew
8.6
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
4.0
OkaySteven,Sep 2026
OGG - HNL
Related info for your journey
Find useful and relevant information for your journey from St. Louis to Philadelphia. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Philadelphia?
Book flights to Philadelphia if you plan to visit one of these locationsWildwood
Reading
King of Prussia
Camden
Ocean City
Wildwood Crest
Cherry Hill
Lewes
Plymouth Meeting
Wyomissing
Pottstown
Ephrata
Milford
Dover
Elkton
Essington
Willow Grove
New Castle
Vineland
Millville
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Complete your trip to Philadelphia by adding a car rental and/or hotel reservation to your travel itinerary.
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St. Louis and Philadelphia flights
Browse other St. Louis and Philadelphia flight options. Last updated on September 17, 2026.
Other flights from St. Louis
Browse through other flights departing from St. Louis. Flights are based on user searches made on Cheapflights and were last updated on September 17, 2026.
Other flights to Philadelphia
Explore flights to Philadelphia departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on September 17, 2026.
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Check out other popular destinations found by fellow travelers in 2026
Top 3 airlines flying from St. Louis to Philadelphia
Discover the top 3 airlines that operate flights from St. Louis to Philadelphia. 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 7,457,451 searches. Data last updated September 17, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$118 | Average$243 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$277 | Average$464 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$277 | Average$451 | FlexibilityNo cancel fee | On-time71% |