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St. Louis

$85+ Cheap flights from Pennsylvania to St. Louis (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 7/28. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Jul 24 — Jul 311
Fri 7/24
Fri 7/31
1 adult, Economy
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Cheap flight deals from Pennsylvania to St. Louis

Cheapest flights from Pennsylvania to St. Louis
Explore the most affordable flight options available from Pennsylvania to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 24, 2026.

This Kiwi.com deal was found by Cheapflights users on 6/22. 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 7/294:30 pm
PHL
-
STL
1 stop26h 07m
Frontier
Fri 8/74:57 pm
STL
-
PHL
1 stop18h 25m
Frontier
Deal found 6/22$170
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 8/74:40 pm
PHL
-
STL
1 stop17h 17m
Frontier
Mon 8/104:57 pm
STL
-
PHL
1 stop13h 18m
Frontier
Deal found 6/23$176
This Kiwi.com deal was found by Cheapflights users on 6/22. 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 8/48:30 am
PHL
-
STL
1 stop10h 07m
Frontier
Sun 8/96:34 pm
STL
-
PHL
1 stop11h 41m
Frontier
Deal found 6/22$177
This Kiwi.com deal was found by Cheapflights users on 6/22. 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 9/295:28 pm
PHL
-
STL
1 stop17h 12m
Frontier
Fri 10/210:35 am
STL
-
PHL
1 stop6h 40m
Frontier
Deal found 6/22$178
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 7/154:30 pm
PHL
-
STL
1 stop26h 07m
Frontier
Sun 7/196:34 pm
STL
-
PHL
1 stop11h 41m
Frontier
Deal found 6/23$179
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 10/112:43 pm
PHL
-
STL
1 stop21h 57m
Frontier
Mon 10/510:35 am
STL
-
PHL
1 stop20h 01m
Frontier
Deal found 6/23$180
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 7/134:40 pm
PHL
-
STL
1 stop25h 57m
Frontier
Tue 7/216:34 pm
STL
-
PHL
1 stop11h 41m
Frontier
Deal found 6/23$183
This Kiwi.com deal was found by Cheapflights users on 6/22. 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 7/168:30 am
PHL
-
STL
1 stop10h 07m
Frontier
Sun 7/196:34 pm
STL
-
PHL
1 stop11h 41m
Frontier
Deal found 6/22$185
This Kiwi.com deal was found by Cheapflights users on 6/22. 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 7/134:40 pm
PHL
-
STL
1 stop25h 57m
Frontier
Thu 7/166:34 pm
STL
-
PHL
1 stop11h 41m
Frontier
Deal found 6/22$189
This American Airlines deal was found by Cheapflights users on 6/24. 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 8/178:59 pm
PIT
-
STL
1 stop4h 15m
American Airlines
Wed 8/196:00 am
STL
-
PIT
1 stop4h 54m
American Airlines
Deal found 6/24$201
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 10/15:28 pm
PHL
-
STL
1 stop17h 12m
Frontier
Sun 10/410:35 am
STL
-
PHL
1 stop11h 36m
Frontier
Deal found 6/23$208
This Frontier deal was found by Cheapflights users on 6/24. 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 8/186:00 am
PHL
-
STL
1 stop11h 16m
Frontier
Tue 8/256:45 pm
STL
-
PHL
1 stop10h 45m
Frontier
Deal found 6/24$210

Find flight deals from Pennsylvania to St. Louis

Keep the following information in mind while searching for Pennsylvania to St. Louis flight deals. Data was last updated June 24, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$170
(Kiwi.com)

One-way from

$85
(Trip.com)

Popular in

June

Cheapest in

August

Average price

$483

Good round-trip deal

$343 or less

Good one-way deal

$180 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 Pennsylvania to Lambert-St Louis
Search Deals
One-way flight from Pennsylvania to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 8% potential increase in price ($37 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
Search Deals
Price to beat on a round-trip flight from Pennsylvania to Lambert-St Louis.
Search Deals
Price to beat on a one-way flight from Pennsylvania to Lambert-St Louis.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Pennsylvania 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 June 24, 2026.
Use the filters below to find and compare flights from Pennsylvania to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 7/28

5:50 am-1:05 pm

1 stop8h 15m

Lambert-St Louis

Wed 7/29

7:10 pm-9:50 pm

Nonstop1h 40m

$229

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 8/18

5:50 am-9:54 am

1 stop5h 04m

Lambert-St Louis

Thu 8/20

12:52 pm-8:30 pm

1 stop6h 38m

$242

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 10/6

11:45 am-3:58 pm

1 stop5h 13m

Lambert-St Louis

Thu 10/8

5:30 pm-12:19 am

1 stop5h 49m

$242

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Wed 9/23

7:20 pm-8:00 pm

Nonstop1h 40m

Lambert-St Louis

Fri 9/25

4:15 pm-9:50 pm

1 stop4h 35m

$261

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Wed 10/7

7:00 am-12:56 pm

1 stop6h 56m

Lambert-St Louis

Sun 10/11

5:30 pm-12:19 am

1 stop5h 49m

$266

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 8/6

6:00 am-9:54 am

1 stop4h 54m

Lambert-St Louis

Mon 8/10

12:52 pm-8:55 pm

1 stop7h 03m

$271

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 8/25

6:30 am-11:17 am

1 stop5h 47m

Lambert-St Louis

Wed 8/26

8:00 am-1:15 pm

1 stop4h 15m

$276

Washington, D.C.St. Louis

DCA - STL

DCASTL

Washington, D.C. Reagan-National

Tue 8/4

11:40 am-5:55 pm

2 stops7h 15m

Lambert-St Louis

Wed 8/5

8:25 am-2:15 pm

1 stop4h 50m

$277

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 9/1

12:35 pm-6:45 pm

1 stop7h 10m

Lambert-St Louis

Tue 9/8

7:15 am-4:00 pm

2 stops7h 45m

$278

Washington, D.C.St. Louis

DCA - STL

DCASTL

Washington, D.C. Reagan-National

Thu 10/8

6:00 am-12:30 pm

2 stops7h 30m

Lambert-St Louis

Mon 10/12

8:25 am-3:20 pm

1 stop5h 55m

$284

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/24

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Pennsylvania to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Pennsylvania 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 Pennsylvania to St. Louis

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

Currently, July is the cheapest month in which you can book a flight from Pennsylvania to St. Louis (average of $95). Flying from Pennsylvania to St. Louis in March is currently the most expensive (average of $264). 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 PA to STL?

Find hourly flight availability from Pennsylvania 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 June 24, 2026.

When flying from Pennsylvania to St. Louis, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 15% versus a flight in the morning.

Weekly flight availability from Pennsylvania to St. Louis

Explore weekly flight availability from Pennsylvania to St. Louis. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 24, 2026.

The most flights from USPA to STL are scheduled on a Monday (8 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (5 on average).

How much does it cost to fly round-trip from Pennsylvania to St. Louis?

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

To ensure you get the cheapest price possible for a flight from Pennsylvania to St. Louis, you should look to book at least 37 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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

Use this chart to determine the cheapest time to fly round-trip from Pennsylvania to St. Louis. Price data was last updated on June 20, 2026.

Travelers seeking maximum savings on their Pennsylvania to St. Louis flight should consider departing on Thursday at noon 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.

Related info for your journey

Find useful and relevant information for your journey from Pennsylvania 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 airport do you fly into for flights to St. Louis from Pennsylvania?

    Located just 12.7 mi from the city center, Lambert-St Louis (STL) is the airport most travelers will use when flying to St. Louis from Pennsylvania.

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

    Flights from Pennsylvania to Lambert-St Louis have been viewed 43 times in the past calendar month.

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

    Southwest, Delta, and United Airlines can get you from Pennsylvania to St. Louis in just under 5h 04m. Your travel time can differ by up to 3h 11m. There are 552 mi between Pennsylvania and St. Louis. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

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

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $61. Users have also found prices from $108 and $125 on Southwest and American Airlines, respectively.

  • What are the most popular routes from Pennsylvania to St. Louis?

    While some choose either New York LaGuardia - Lambert-St Louis or New York John F Kennedy Intl - Lambert-St Louis, Newark - Lambert-St Louis is the most popular route from Pennsylvania to St. Louis.

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

    Consider Republic Airways (100%), American Airlines (87%) or British Airways (78%) when booking your flight. These represent the most reliable airlines when flying from Pennsylvania to St. Louis.

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

    The cheapest flight price from Pennsylvania to St. Louis is $146. On average you can expect to pay $471. The most popular route, (Newark - Lambert-St Louis), can usually be booked for $242.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Pennsylvania 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 Pennsylvania to St. Louis?

    Currently, July is the cheapest month in which you can book a flight from Pennsylvania to St. Louis (average of $95). Flying from Pennsylvania to St. Louis in March is currently the most expensive (average of $264). 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
Eureka
Maryland Heights
Collinsville
Wentzville
Glencoe
Chesterfield
Alton
Farmington

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Pennsylvania to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
Newark to Kansas City flights
Newark to St. Louis flights
Hobby to Kansas City flights
LaGuardia to St. Louis flights
George Bush Intcntl to Kansas City flights
Dulles Intl to Kansas City flights
Los Angeles to Kansas City flights
John F Kennedy Intl to Kansas City flights
O'Hare Intl to Kansas City flights
LaGuardia to Kansas City flights
Seattle to Kansas City flights
Denver to Kansas City flights
San Francisco to Kansas City flights
Reagan-National to Kansas City flights
Dallas/Fort Worth to Kansas City flights
John F Kennedy Intl to St. Louis flights
Denver to St. Louis flights
Baltimore to Kansas City flights
Dallas/Fort Worth to St. Louis flights
Seattle to St. Louis flights
Dulles Intl to St. Louis flights
Boston to Kansas City flights
Boston to St. Louis flights
Baltimore to St. Louis flights
Miami to Kansas City flights
Orlando to Kansas City flights
Philadelphia to Kansas City flights
Orlando to St. Louis flights
Los Angeles to St. Louis flights
Atlanta to St. Louis flights
Sky Harbor Intl to Kansas City flights
San Francisco to St. Louis flights
Ontario to Kansas City flights
Reagan-National to St. Louis flights
Philadelphia to St. Louis flights
Atlanta to Kansas City flights
Midway to Kansas City flights
Minneapolis to Kansas City flights
Charlotte to St. Louis flights
Hobby to St. Louis flights
Raleigh to Kansas City flights
Sky Harbor Intl to St. Louis flights
Tampa to Kansas City flights
San Diego to Kansas City flights
Austin to Kansas City flights
Detroit to Kansas City flights
George Bush Intcntl to St. Louis flights
Denver to Springfield flights
San Diego to St. Louis flights
O'Hare Intl to St. Louis flights

Top 5 airlines flying from Pennsylvania to St. Louis

Discover the top 5 airlines that operate flights from Pennsylvania 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 June 24, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$153Average$226FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$170Average$383FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$196Average$393FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$227Average$400FlexibilityNo cancel feeOn-time63%
DeltaCheapest$251Average$401FlexibilityNo cancel feeOn-timeN/A

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