$43+ Cheap flights from Philadelphia to St. Louis (PHL - STL)
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.
PHL — STL
Oct 14 — Oct 211
Round-trip
1 adult, Economy
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Find cheap flights from Philadelphia to St. Louis 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 Philadelphia to Lambert-St Louis are usually found in September or October, booked 65 days in advance, depart on a Wednesday or Saturday and return on a Friday
Cheap flight deals from Philadelphia to St. Louis
Cheapest
Best
Last-minute
One-way
Cheapest flights from Philadelphia to St. LouisExplore 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 September 14, 2026.
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 September 14, 2026.
This Delta deal was found by Cheapflights users on 9/10. 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.
Wed 9/305:20 am -
1 stop4h 40m
Wed 9/301:55 pm -
1 stop4h 24m
Deal found 9/10![Delta logo]()
$277
This Southwest deal was found by Cheapflights users on 9/10. 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 10/126:25 am -
Nonstop2h 20m
Wed 10/1412:10 pm -
Nonstop2h 15m
Deal found 9/10![Southwest logo]()
$278
This Frontier deal was found by Cheapflights users on 9/11. 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.
Mon 9/287:15 am -
1 stop10h 19m
Thu 10/84:30 pm -
1 stop6h 13m
Deal found 9/11![Frontier logo]()
$279
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/196:00 am -
1 stop6h 19m
Sun 11/225:59 pm -
1 stop5h 54m
Deal found 9/13![Frontier logo]()
$280
This Frontier deal was found by Cheapflights users on 9/9. 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.
Sun 10/255:45 pm -
1 stop6h 28m
Thu 10/294:26 pm -
1 stop6h 16m
Deal found 9/9![Frontier logo]()
$281
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.
Tue 9/2912:40 pm -
2 stops23h 52m
Mon 10/52:29 pm -
1 stop15h 47m
Deal found 9/13![Frontier logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 10/166:00 am -
1 stop11h 58m
Sun 10/185:53 pm -
1 stop19h 28m
Deal found 9/10![Frontier logo]()
$283
This Orbitz 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/285:01 am -
1 stop19h 58m
Mon 11/301:20 pm -
1 stop18h 15m
Deal found 9/12![Frontier logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 9/10. 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.
Thu 10/18:02 pm -
2 stops18h 08m
Fri 10/25:19 pm -
1 stop5h 50m
Deal found 9/10![Frontier logo]()
$285
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 10/25:32 pm -
2 stops26h 45m
Mon 10/52:29 pm -
1 stop7h 49m
Deal found 9/13![Frontier logo]()
$287
This American Airlines deal was found by Cheapflights users on 9/10. 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.
Fri 11/61:10 pm -
1 stop5h 37m
Tue 11/106:02 am -
Nonstop2h 18m
Deal found 9/10![American Airlines logo]()
$288
Best flights from Philadelphia to St. LouisDiscover carefully curated flight deals from Philadelphia to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 14, 2026.
Discover carefully curated flight deals from Philadelphia to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 14, 2026.
This Southwest deal was found by Cheapflights users on 9/10. 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 10/166:55 am -
1 stop6h 20m
Fri 10/162:30 pm -
2 stops6h 25m
Deal found 9/10![Southwest logo]()
$324
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 10/167:40 pm -
Nonstop2h 20m
Mon 10/197:50 pm -
Nonstop2h 25m
Deal found 9/13![Southwest logo]()
$334
This Southwest deal was found by Cheapflights users on 9/9. 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.
Sun 10/186:20 am -
Nonstop2h 20m
Tue 10/2012:15 pm -
2 stops7h 50m
Deal found 9/9![Southwest logo]()
$357
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 10/136:40 pm -
Nonstop2h 20m
Tue 10/202:25 pm -
1 stop5h 40m
Deal found 9/13![Southwest logo]()
$377
This Southwest deal was found by Cheapflights users on 9/11. 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 10/136:25 am -
Nonstop2h 20m
Wed 10/1410:55 am -
2 stops9h 40m
Deal found 9/11![Southwest logo]()
$382
This Southwest deal was found by Cheapflights users on 9/10. 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.
Wed 11/182:45 pm -
Nonstop2h 35m
Fri 11/208:10 pm -
Nonstop2h 05m
Deal found 9/10![Southwest logo]()
$383
This Southwest deal was found by Cheapflights users on 9/11. 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.
Thu 11/127:30 am -
2 stops8h 50m
Sun 11/152:05 pm -
2 stops8h 05m
Deal found 9/11![Southwest logo]()
$427
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.
Sun 12/61:50 pm -
2 stops8h 30m
Wed 12/911:45 am -
2 stops9h 20m
Deal found 9/13![Southwest logo]()
$445
This Southwest deal was found by Cheapflights users on 9/11. 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 10/231:55 pm -
2 stops7h 00m
Sun 10/254:55 pm -
2 stops7h 05m
Deal found 9/11![Southwest logo]()
$446
This Southwest deal was found by Cheapflights users on 9/9. 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 9/286:20 am -
Nonstop2h 15m
Thu 10/14:05 pm -
1 stop6h 20m
Deal found 9/9![Southwest logo]()
$449
Last-minute flights from Philadelphia to St. LouisDiscover last-minute flight deals from Philadelphia to St. Louis. Data last updated September 14, 2026 and is based on user searches.
Discover last-minute flight deals from Philadelphia to St. Louis. Data last updated September 14, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 9/11. 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.
Mon 9/287:15 am -
1 stop10h 19m
Thu 10/84:30 pm -
1 stop6h 13m
Deal found 9/11![Frontier logo]()
$279
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.
Tue 9/2912:40 pm -
2 stops23h 52m
Mon 10/52:29 pm -
1 stop15h 47m
Deal found 9/13![Frontier logo]()
$282
This Delta deal was found by Cheapflights users on 9/10. 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.
Wed 9/305:20 am -
1 stop4h 40m
Wed 9/301:55 pm -
1 stop4h 24m
Deal found 9/10![Delta logo]()
$277
This Kiwi.com deal was found by Cheapflights users on 9/10. 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.
Thu 10/18:02 pm -
2 stops18h 08m
Fri 10/25:19 pm -
1 stop5h 50m
Deal found 9/10![Frontier logo]()
$285
This American Airlines deal was found by Cheapflights users on 9/10. 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 10/18:54 am -
Nonstop2h 35m
Fri 10/211:01 am -
1 stop7h 22m
Deal found 9/10![American Airlines logo]()
$288
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 10/25:32 pm -
2 stops26h 45m
Mon 10/52:29 pm -
1 stop7h 49m
Deal found 9/13![Frontier logo]()
$287
This Expedia 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/45:15 am -
1 stop12h 19m
Sat 10/244:30 pm -
1 stop6h 13m
Deal found 9/13![Frontier logo]()
$280
This Expedia deal was found by Cheapflights users on 9/9. 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.
Thu 10/86:00 am -
1 stop11h 58m
Sun 10/114:30 pm -
1 stop16h 02m
Deal found 9/9![Frontier logo]()
$289
This Southwest deal was found by Cheapflights users on 9/10. 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 10/126:25 am -
Nonstop2h 20m
Mon 10/197:50 pm -
Nonstop2h 25m
Deal found 9/10![Southwest logo]()
$278
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 10/166:00 am -
1 stop11h 58m
Sun 10/185:53 pm -
1 stop19h 28m
Deal found 9/10![Frontier logo]()
$283
This Frontier deal was found by Cheapflights users on 9/9. 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.
Sun 10/255:45 pm -
1 stop6h 28m
Thu 10/294:26 pm -
1 stop6h 16m
Deal found 9/9![Frontier logo]()
$281
One-way flights from Philadelphia to St. LouisSearch for one-way flight options from Philadelphia to St. Louis. Find affordable one-way fares based on user searches. Data last updated September 14, 2026.
Search for one-way flight options from Philadelphia to St. Louis. Find affordable one-way fares based on user searches. Data last updated September 14, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 10/78:41 am -
1 stop5h 29m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$43
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 11/105:22 pm -
1 stop25h 18m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$44
This Trip.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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/126:03 pm -
1 stop24h 37m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$56
This Super.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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/1112:36 pm -
1 stop6h 04m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$57
This Kiwi.com deal was found by Cheapflights users on 9/9. 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.
Thu 12/102:45 pm -
1 stop17h 24m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/9![Frontier logo]()
$61
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.
Mon 10/128:30 am -
1 stop10h 10m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$75
This Frontier deal was found by Cheapflights users on 9/10. 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.
Wed 11/1812:36 pm -
1 stop6h 04m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$77
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.
Thu 10/156:03 pm -
1 stop24h 37m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$81
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 September 14, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $277 (Delta) |
One-way from | $43 (Kiwi.com) |
Popular in | June |
Cheapest in | September |
Average price | $353 |
Good round-trip deal | $345 or less |
Good one-way deal | $208 or less |
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 7,457,451 searches. Data last updated September 14, 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
Cheapest round-trip
Quickest round-trip
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Wed 10/21
6:25 am-7:45 am
Nonstop2h 20m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$129
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Mon 11/9
7:25 pm-9:00 pm
Nonstop2h 35m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$129
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Tue 12/8
6:00 am-7:45 am
Nonstop2h 45m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$129
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Tue 10/6
6:25 am-7:45 am
Nonstop2h 20m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$129
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Sat 11/14
5:45 pm-11:16 pm
1 stop6h 31m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$139
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Wed 12/9
7:00 am-12:41 am
2 stops18h 41m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$142
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Fri 11/6
6:00 am-7:40 am
Nonstop2h 40m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$150
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Tue 10/13
6:40 pm-8:00 pm
Nonstop2h 20m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$150
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Mon 10/12
6:25 am-7:45 am
Nonstop2h 20m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$150
PhiladelphiaSt. Louis
PHL Philadelphia - STL Lambert-St Louis
PHLSTL
Philadelphia
Mon 11/16
5:22 pm-3:23 pm
2 stops47h 01m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$154
Showing 1-10 of 20 resultsSorted by cheapest first
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 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 |
- 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.
PHL-STL
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
Prices
Airlines
How far ahead should I book a flight from Philadelphia to St. Louis?
Booking 42 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, September is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $353). Flying from Philadelphia to St. Louis in June is currently the most expensive (average of $497). 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 September 14, 2026.
It’s optimal to fly from Philadelphia to St. Louis in the afternoon. By choosing this option you can save up to 9% on the cost of your flight, compared to a flight in the morning.
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 September 12, 2026.
Travelers seeking maximum savings on their Philadelphia to St. Louis flight should consider departing on Saturday 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
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 September 14, 2026.
See what other customers who have flown with Southwest,American Airlines, andFrontier 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.
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Crew
8.6
Overall
8.0
Food
7.0
Reviews
1 / 20
10.0
ExcellentCourtney,Sep 2026
DEN - STL
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Crew
8.6
Overall
8.0
Food
7.0
Reviews
1 / 20
10.0
ExcellentCourtney,Sep 2026
DEN - STL
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Crew
8.6
Overall
8.0
Food
7.0
Reviews
1 / 20
10.0
ExcellentCourtney,Sep 2026
DEN - STL
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Crew
8.6
Overall
8.0
Food
7.0
Reviews
1 / 20
10.0
ExcellentCourtney,Sep 2026
DEN - STL
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.
Traveling to a place near St. Louis?
Book flights to St. Louis if you plan to visit one of these locationsFairview Heights
O'Fallon
Fenton
Swansea
Eureka
Maryland Heights
Collinsville
Wentzville
Edwardsville
Glencoe
Chesterfield
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Top 3 airlines flying from Philadelphia to St. Louis
Discover the top 3 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 7,457,451 searches. Data last updated September 14, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$144 | Average$229 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$277 | Average$446 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$277 | Average$435 | FlexibilityNo cancel fee | On-time71% |