PHL - STL

$89 Find Cheap Flights from Philadelphia to St. Louis

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Philadelphia to St. Louis departing on 5/5. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
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KAYAK searches hundreds of travel sites at once for deals on flights to St. Louis

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Philadelphia to St. Louis, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Philadelphia to St. Louis, as well as popular online travel agencies
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Flights Deals

Cheap Flight Deals from Philadelphia to St. Louis (PHL-STL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Philadelphia to St. Louis that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.

Recent round-trip flight deals from Philadelphia to St. Louis

KAYAK's recommended round-trip deals from the most popular airlines that fly from Philadelphia to St. Louis.
Discover the best prices for you by selecting your travel dates on KAYAK.
Frontier Logo
4:33 pm - 12:06 amPHL-STL
8h 33m1 stop
Frontier Logo
5:45 pm - 7:36 amSTL-PHL
12h 51m1 stop
$178Frontier
Find Deal
Mon, May 12 - Wed, May 14
Frontier Logo
10:59 pm - 12:06 amPHL-STL
26h 07m1 stop
Frontier Logo
5:45 pm - 7:36 amSTL-PHL
12h 51m1 stop
$181Frontier
Find Deal
Sun, May 11 - Sat, May 17
 Logo
12:59 pm - 9:09 amPHL-STL
21h 10m1 stop
 Logo
10:10 am - 10:43 pmSTL-PHL
11h 33m1 stop
Thu, May 29 - Thu, Jun 5
 Logo
4:00 pm - 6:41 pmPHL-STL
27h 41m2 stops
 Logo
10:10 am - 10:43 pmSTL-PHL
11h 33m1 stop
Thu, Jun 5 - Sat, Jun 7
American Airlines Logo
10:53 am - 12:27 pmPHL-STL
2h 34mnonstop
American Airlines Logo
6:00 am - 9:11 amSTL-PHL
2h 11mnonstop
$301American Airlines
Find Deal
Tue, May 20 - Wed, May 21
American Airlines Logo
7:14 pm - 8:58 pmPHL-STL
2h 44mnonstop
American Airlines Logo
5:00 am - 11:23 amSTL-PHL
5h 23m1 stop
$311American Airlines
Find Deal
Tue, May 20 - Wed, May 21
Southwest Logo
8:05 am - 9:30 amPHL-STL
2h 25mnonstop
Southwest Logo
8:25 am - 11:35 amSTL-PHL
2h 10mnonstop
$320Southwest
Find Deal
Wed, Jun 4 - Sat, Jun 7
Delta Logo
6:15 pm - 11:39 pmPHL-STL
6h 24m1 stop
Delta Logo
2:18 pm - 7:22 pmSTL-PHL
4h 04m1 stop
$321Delta
Find Deal
Tue, Aug 12 - Wed, Aug 13
Southwest Logo
8:05 am - 9:30 amPHL-STL
2h 25mnonstop
Southwest Logo
8:35 am - 6:45 pmSTL-PHL
9h 10m1 stop
$330Southwest
Find Deal
Wed, Jun 4 - Sat, Jun 7
Delta Logo
6:00 am - 9:33 amPHL-STL
4h 33m1 stop
Delta Logo
7:05 pm - 12:27 amSTL-PHL
4h 22m1 stop
$340Delta
Find Deal
Wed, Aug 6 - Thu, Aug 14
Expert advice

Expert advice for your flight from Philadelphia to St. Louis

 
Snippets provided in this section are AI-generated based on a summarization of KAYAK-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Airlines
American Airlines

Consider Main Cabin Extra for early boarding and complimentary drinks on short flights.


Download the American Airlines app for inflight entertainment on domestic flights without seatback screens.

Southwest

Southwest offers two free checked bags, ideal for travelers with lots of luggage.


Use EarlyBird Check-In for a better boarding position, avoiding middle seats.

Read more about Southwestby Blane Bachelor
Airports
PHL

PHL offers public transportation via SEPTA's Airport Regional Rail Line, providing a cost-effective 30-minute trip to Center City Philadelphia.

Read more about PHLby Harriet Baskas
STL

Use MetroLink for easy access from STL to downtown St. Louis, avoiding rush hour traffic with convenient Red Line connections.

Read more about STLby Yulia Denisyuk
Our travel experts
Harriet Baskas

Harriet Baskas

Expert on American Airlines and PHL

Harriet Baskas

Harriet Baskas

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
Blane Bachelor

Blane Bachelor

Expert on Southwest

Blane Bachelor

Blane Bachelor

Blane Bachelor is a journalist and editor specializing in travel and aviation who writes regularly for top global outlets. Born and raised in Florida, Blane has worked and lived in four countries, including the Netherlands, where she’s currently based with her family. Her favorite way to get to know a new destination is by running or riding a bike around town – or hearing a spooky ghost story about local history. She will always choose the window seat.

Read more
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia Denisyuk

Yulia Denisyuk

Yulia is a freelance journalist who’s dispatched from 90+ countries. Her work focuses on cultures, adventure trips and air travel, appearing in NatGeo, NYT, CNTraveler, and more. For past assignments, she’s stayed with nomads in Mongolia and learned the art of Imigongo in Rwanda. She’s based in Chicago; in winter she often questions that decision.

Read more
Useful Info

KAYAK's insights & trends for Philadelphia to St. Louis flights

Get data-powered insights and trends into flights from Philadelphia to St. Louis to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from Philadelphia to St. Louis?

The average price of all round-trip flights from Philadelphia to St. Louis clicked on KAYAK for each day over the last 12 months.

For Philadelphia to St. Louis, Saturday is the cheapest day to fly on average and Sunday is the most expensive. Flying from St. Louis back to Philadelphia, the best deals are generally found on Friday, with Sunday being the most expensive.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Philadelphia to St. Louis, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Philadelphia to St. Louis is July, where tickets cost $201 (return) on average. On the other hand, the most expensive months are April and March, where the average cost of round-trip tickets is $450 and $429 respectively.

Can I save money by flying with a layover from Philadelphia to St. Louis?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at $324 on average.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Philadelphia to St. Louis, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Philadelphia to St. Louis, you should book around 4 weeks before departure. For the absolute cheapest price, our data suggests you should book 13 weeks before departure.

Good to know

Low seasonJanuary
High seasonJuly
Cheapest flight$89
Best time to beat the crowds but there is an average 12% increase in price.
Most popular time to fly and prices are also 42% lower on average.
Flight from Philadelphia to St. Louis

When to book flights from Philadelphia to St. Louis

Are your dates flexible? Find out the best times to travel from Philadelphia to St. Louis based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Philadelphia to St. Louis

  • How do I get from Lambert St. Louis Airport (STL) to the city center?

    MetroLink provides train service from the airport to the city center. The train departs from Lambert Airport Terminal 1 station and arrives at Stadium Station. It typically runs 406 times weekly with the duration of the ride being around 45 minutes. Public buses also offer service the route between the airport and the city center with a journey time of around 45 minutes. The cost will vary depending on the bus you choose.

  • What seat options are available on Frontier flights from Philadelphia to St. Louis?

    Frontier Airlines offers several seat options, including standard seats, which are the regular seats, and stretch seats, which are seats with additional legroom that are available for purchase for an additional fee, and are often located in the front of the plane or the emergency exit rows. Frontier Airlines offer passengers the option to choose their own seats for a fee, instead of having the airline randomly assign them.

  • What is the luggage allowance on Southwest flights from Philadelphia to St. Louis?

    Southwest Airlines allows passengers on flights from Philadelphia to St. Louis to check up to two bags for free as part of the fare, provided that the bags do not exceed 50 lbs in weight and 62 inches in size. Passengers are allowed to bring one carry-on bag and one personal item on board the aircraft. The carry-on bag must not exceed 24 inches in length, 16 inches in width, and 10 inches in height. In addition, passengers will be charged an additional fee of $75 per one-way trip for bags that exceed the weight limit of 50 lbs, up to a maximum weight of 100 lbs.

  • What services are offered by Alaska Airlines on economy class flights from Philadelphia to St. Louis?

    Alaska Airlines offers several services on economy class flights including limited food and drinks, which may include a choice of snacks or meals, free soft drinks, coffee, and tea on all flights, leather headrests and a wide range of in-flight entertainment options, and standard economy seats with average legroom and seat-back pockets for storage.

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

    In the last 3 days, the lowest price for a flight from Philadelphia to St. Louis was $89 for a one-way ticket and $178 for a round-trip.

  • Do I need a passport to fly between Philadelphia and St. Louis?

    No, a passport isn't needed to fly from Philadelphia to St. Louis. However, local authorities might ask for an official ID.

  • Which airports will I be using when flying from Philadelphia to St. Louis?

    Philadelphia and St. Louis are both served by 1 main airport. You will leave Philadelphia from Philadelphia and will be arriving at Lambert-St Louis.

  • Which airlines offer Wi-Fi service onboard planes from Philadelphia to St. Louis?

    American Airlines, and Delta offer inflight Wi-Fi service on the Philadelphia to St. Louis flight route.

  • Which aircraft models fly most regularly from Philadelphia to St. Louis?

    The Boeing 737 MAX 8 is the aircraft model that flies most regularly on the Philadelphia to St. Louis flight route.

  • Which airline alliances offer flights from Philadelphia to St. Louis?

    oneworld is the only airline alliance operating flights between Philadelphia and St. Louis.

  • On which days can I fly direct from Philadelphia to St. Louis?

    There are nonstop flights from Philadelphia to St. Louis on a daily basis.

  • Which is the best airline for flights from Philadelphia to St. Louis, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from Philadelphia to St. Louis are Southwest and Delta. With an average price for the route of $417 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $318 and an overall rating of 8.0.

  • How does KAYAK find such low prices on flights from Philadelphia to St. Louis?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Philadelphia to St. Louis.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Philadelphia to St. Louis?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Louis from Philadelphia is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Philadelphia to St. Louis?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to St. Louis with an airline and back to Philadelphia with another airline. Booking your flights between Philadelphia and STL can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Philadelphia to St. Louis?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to St. Louis from Philadelphia up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Philadelphia to St. Louis

  • Looking for a cheap flight? 25% of our users found flights on this route for $188 or less one-way and $357 or less round-trip.
  • Flights from Philadelphia (PHL) to St. Louis (STL) have layovers in various cities depending on the airline. Some of these cities include Orlando (MCO), Dallas (DFW), Atlanta (ATL), Minneapolis (MSP), Denver (DEN), and Charlotte (CLT).
  • Flights from Philadelphia to St. Louis take approximately 7 hours so passengers can consider flying Business class on American Airlines flights. A Business class ticket on American Airlines gets you access to the Flagship Lounge at the airport, priority boarding, and lie-flat seats, making the overall journey more comfortable.
  • United Airlines is using sustainable aviation fuel (SAF) to reduce carbon emissions, with plans to use lower-carbon fuels on routes like those from Philadelphia to St. Louis.
  • Delta Air Lines provides wheelchair assistance to passengers who require assistance throughout their travels on flights from Philadelphia to St. Louis. The airline provides additional assistance at the airport, as well as on board flights, for passengers with reduced mobility or those traveling with a caregiver.
  • Lambert St. Louis Airport (STL) gives access to several other cities in the region. These include Berkeley, Hazelwood, Saint Ann, Bridgeton, Florissant, Ferguson, Maryland Heights, Overland, Creve Coeur, and Chesterfield.

Prefer to fly direct from Philadelphia to St. Louis?

Find which airlines fly direct from Philadelphia Airport to Lambert-St Louis Airport, which days they fly and book direct flights.

Direct departures

Philadelphia to Lambert-St Louis

Monday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Tuesday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Wednesday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Thursday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Friday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Saturday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Sunday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

See more direct flights

Direct returns

Lambert-St Louis to Philadelphia

Monday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

Tuesday

American Airlines, British Airways, Iberia, +2 more

American Airlines, British Airways, +3 more

Wednesday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

Thursday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

Friday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

Saturday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

Sunday

Aer Lingus, American Airlines, British Airways, +3 more

Aer Lingus, American Airlines, +4 more

See more direct flights
See more direct flights

Top 4 airlines serving from Philadelphia to St. Louis

 
See real verified KAYAK customer reviews for airlines flying from Philadelphia to St. Louis. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Philadelphia to St. Louis? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4294 reviews
7.1Food
8.2Boarding
8.6Crew
7.6Entertainment
8.0Comfort
Airline reviews

It is southwest seat was ok. Not the most comfortable seat

8.0 ExcellentJohn, Apr 2025PVD - FLL
Read more Southwest reviews

It is southwest seat was ok. Not the most comfortable seat

I’ve always loved Southwest. No issues at all. I was flying standby and the gate agent was extremely friendly and helpful. Boarding was smooth and I was able to get a window seat in the emergency exit row. Crew was fantastic! They were very professional and accommodating. We had to divert from our destination due to weather but the flight crew kept everyone at ease and informed us of all pertinent information. Excellent flight

The price of the tickets isn't matching the flight experience. No matter how long the flight is, you're only getting pretzels. The flight attendants looked unkept and over it.

Plz don't take away free bags and free seating

The seats were a bit cramped and worn, but otherwise okay.

I would have liked to arrive on time - not 5 hours late!

After a 3 hour layover in Denver my flight was delayed over 5 hours! No explanation; no assistance; no offer to provide compensation; no one at Southwest was willing to offer any assistance. 8 hours in the Denver airport - ridiculous!

It was a perfect flight in all aspects! Both legs!

Only one drink pass through the cabin for a 4 hour flight. Quite rough and bumpy landing.

Boarding process, crew were good. But the seats were so uncomfortable that was all I could focus on. I literally had to sit forward so that all 3 of us could fit in row. I will try to avoid Southwest in the future for any flights over 60 minutes.

Delta is my preferred airline. I've traveled with them for years. On time in most cases, good communication, easy to use app. Most planes are pretty nice. I was on a CRJ 700/900 however, which was pretty badly aged inside and needed a refresh. No infotainment, unreliable wifi, best to download before boarding or bring a book. Food choices are really just snacks on this flight, nice variety but about what you'd expect. Great staff and prompt in departure and early arrival too. Overall quite satisfied.

Crew was friendly Love the entertainment in the seat head rest.

Delta flight was on time, seats were comfortable, and crew was nice.

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Delayed take-off. Very small plane so very scary with lots of bumps during the flight. Would never fly Delta on short flights in small 80 seaters plane again! Felt relieved when landed.

The worst part was I was NOT allowed in the lounge even though I was holding a first class ticket and have a premium American Express card. I have flown Business or First Class with many airlines. Delta is the ONLY one who does not extend this courtesy to anyone except people who hold the very expensive American Express card. As a result, I won’t fly Delta if I have any other choice.

A little bumpy ride . No food was being provided due the the turbulence. That was ok it was a short flight to my standards.

Simply outstanding. Their new lounge for Delta One customers is a cut above the rest.

The Dekta Rep that checked us in was great. She's very personable, pleasant, and can tell she enjoys her job.

The plane was old with small storage areas that had problems closing/latching and not enough storage for everyone, and worn, damaged seats. Service was great but feel a little unsafe on such well used planes.

Everything about the flight was lovely…We left early, arrived early, cabin crew were efficient and helpful. Flight was easy and most pleasant.

One bottle of water and a package of cookies for comfort plus. We had to literally beg a flight attendant for an extra bottle of water later in the flight due to feeling dehydrated.

late again! but its my only option to not take 9 hours to get to Memphis

Almost everything was outstanding. First, we boarded on time and the flight crew did a great job getting everyone seated. Then the pilots took their time and care to make sure the plane was full de-iced three times as there was a bad ice storm a few hours earlier. The plane ride was smooth and comfortable and even the economy seats had decent room and comfort. Flight Attendant Lisa went above and beyond to make sure I was comfortable - she is outstanding. The only thing wrong with the flight, and it is something which needs to be addressed, is that the gate to gate time was over 6.5 hours and not one meal was served. The only thing offered to eat were two small cookies for a transcontinental flight - unacceptable. Charge me more but give me a meal for a long flight. Thankfully Lisa found something for me.

Very poor. Our special services attendant gave us incorrect information. I also was mishandled at landing. There was no wheelchair waiting. I fell deboarding the plane. Appalling!

Improvements in communication and empathy are absolutely necessary for American Airlines staff (top down). It’s like they are numb to the needs of their customers.

I had a very unpleasant encounter with one man from customer service: he was extremely rude and miserable. And his condition was reflected on his decision to send me to the worst airport hotel and get an awful flight connection. My hotel shuttle had never arrived and I had to book another hotel. People served by other representatives got a much better treatment and deal.

The flight left a bit late, but arrived close to time expected…With the flight being close to full the crew did well serving drinks to all in a very timely fashion. The flight was a pleasure…

They didn't have any gluten-free snacks, oddly, which I require...or any flavored soda water or decaf tea options, which seems to be standard.

My flight back my reservations were list because they said I didn't pay my pet fee when I had a receipt

The reps working at the airport counter were dumber than a second coat of paint.

My costume jewelry was stolen out of my bag. Got to airport and my bag weighed 45 pounds- 5 pounds over cost me $100 Long lines in tier one. No entertainment No WiFi no free drinks or snacks

Not very good. Paid in excess of $400 for assigned seating for my family and that was not provided. I want that money back.

The seats were hard molded plastic covered in plastic vinyl. And the scam to charge people extra to sit together. Don’t they know we can just ask someone to trade seats. And watching the staff separate young children from parents… super classy. We had to guilt them into offering up our seats. This companies policies suck. Don’t give them your money.

The seats were awful, hard plastic covered in sheet vinyl. The airline tries to scam you into paying extra to get seat together when the flight wasn’t full. They were going to separate a family with young children but my wife who had a row to herself gave up her seat so the young mom could be with her young boys. I’m never giving this airline my money again.

It was a short flight so no food or entertainment….

Seats are uncomfortable but price is good. Guess I can put up with misery for four hours.

I’ve never traveled on Frontier before. If you want basic, no frills, friendly service at great prices then give them a fly!

Cancelled and declined to find alternatives Earlier flight is 2 days later Sent the cancellation notification very late, wish I knew earlier would have stayed to watch the Miami open final game Very disappointing service

The worst flight of my life. Never will I fly frontier again

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

Information on your arrival and departure airports

Compare transportation modes for Philadelphia to St. Louis

Average priceAverage duration
Flights$3242h 25m
Buses$21121h 47m

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