$56 Find Cheap Flights from Philadelphia to St. Charles

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. Charles departing on 2/10. 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.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights from Philadelphia to St. Charles

Travelers love KAYAK
41 299 237 searches in the past 7 days on KAYAK

Save 24% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Free to useThere are no hidden charges or fees.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Everything you should know

Cheapest round-trip
$128
Overall average: $382
Frontier
Tue 1/27Fri 1/30
PHL - STL • 1 stop
Cheapest non-stop
$297
Typical prices: $387-$757
American Airlines
Sat 1/17Tue 1/20
PHL - STL • Non-stop
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to St. Charles!
Flight Deals
Useful Info
Flight Deals

Cheap Flights from Philadelphia to St. Charles (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. Charles 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.
Discover the best prices for you by selecting your travel dates on KAYAK.

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

Tue, Jan 27 - Fri, Jan 30
Frontier Logo
8:25 pm - 11:33 pm
PHL
-
STL
28h 08m1 stop
Frontier Logo
5:42 pm - 2:44 pm
STL
-
PHL
20h 02m1 stop
$128Frontier
Wed, Jan 7 - Tue, Jan 13
Frontier Logo
7:12 pm - 2:48 pm
PHL
-
STL
20h 36m1 stop
Frontier Logo
5:11 pm - 2:58 pm
STL
-
PHL
20h 47m1 stop
$132Frontier
Thu, Jan 22 - Sun, Jan 25
Frontier Logo
9:02 pm - 11:33 pm
PHL
-
STL
27h 31m1 stop
Frontier Logo
5:42 pm - 10:32 pm
STL
-
PHL
27h 50m1 stop
$141Frontier
Thu, Jan 15 - Mon, Jan 19
Frontier Logo
6:00 am - 10:34 pm
PHL
-
STL
17h 34m1 stop
Frontier Logo
8:32 pm - 3:37 pm
STL
-
PHL
18h 05m1 stop
$143Frontier
Wed, Jan 21 - Sat, Jan 24
Frontier Logo
8:25 pm - 11:33 pm
PHL
-
STL
28h 08m1 stop
Frontier Logo
11:00 am - 10:46 pm
STL
-
PHL
10h 46m1 stop
$145Frontier
Wed, Jan 7 - Tue, Jan 13
Multiple Airlines Logo
8:54 pm - 10:33 pm
PHL
-
STL
26h 39m2 stops
Multiple Airlines Logo
5:11 pm - 2:58 pm
STL
-
PHL
20h 47m1 stop
$151Multiple Airlines
Wed, Jan 7 - Sun, Jan 11
Frontier Logo
7:12 pm - 2:48 pm
PHL
-
STL
20h 36m1 stop
Frontier Logo
5:11 pm - 4:53 pm
STL
-
PHL
22h 42m2 stops
$153Frontier
Tue, Feb 10 - Sat, Feb 14
Frontier Logo
6:40 pm - 6:51 am
PHL
-
STL
13h 11m1 stop
Frontier Logo
8:17 pm - 11:18 am
STL
-
PHL
14h 01m1 stop
$157Frontier
Thu, Jan 22 - Sun, Jan 25
Multiple Airlines Logo
8:43 pm - 10:23 am
PHL
-
STL
14h 40m1 stop
Multiple Airlines Logo
5:42 pm - 11:18 am
STL
-
PHL
16h 36m2 stops
$160Multiple Airlines
Thu, Jan 8 - Mon, Jan 12
Frontier Logo
1:38 pm - 10:33 pm
PHL
-
STL
9h 55m1 stop
Frontier Logo
5:11 pm - 12:29 am
STL
-
PHL
6h 18m1 stop
$162Frontier
Useful Info

Good to know

Low seasonFebruary
Cheapest flight$56
Best time to beat the crowds but there is an average 6% increase in price.
Most popular time to fly with an average 17% increase in price.
Flight from Philadelphia to St. Louis

When to book flights from Philadelphia to St. Charles

Are your dates flexible? Find out the best times to travel from Philadelphia to St. Charles based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

FAQs for booking flights from Philadelphia to St. Charles

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

    When flying out of Philadelphia you’ll be using Philadelphia. St. Charles does not have its own airport so you’ll be flying into nearby Lambert-St Louis airport, which is 7.2 mi away.

  • How long does a flight from Philadelphia to St. Charles take?

    Direct flights cover the 811 miles separating Philadelphia and St. Charles in about 2h 30m.

  • How many flights are there between Philadelphia and St. Charles?

    16 direct flights run between Philadelphia and St. Charles on a daily basis. On average, there are about 117 departures each week.

  • What’s the cheapest day of the week to fly between Philadelphia and St. Charles?

    Consider leaving on a Saturday and avoid Mondays if you are looking for the best rates. For your return to Philadelphia, you’ll find the best rates on Wednesdays and the most expensive ones on Saturdays.

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

    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. Charles.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Charles 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. Charles?

    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. Charles with an airline and back to Philadelphia with another airline.

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

    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. Charles from Philadelphia up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines provide the cheapest flights from Philadelphia to St. Charles?

    In the last 72 hours, the cheapest one-way ticket between Philadelphia and St. Charles found on KAYAK was with Frontier for $70. Spirit Airlines offered a round-trip connection from $95 and Frontier from $127.

Top tips for finding cheap flights from Philadelphia to St. Charles

  • There is no airport in St. Charles. Instead, you’ll be flying into St. Louis Lambert Airport when flying between Philadelphia and St. Charles.
  • The cheapest flight from Philadelphia to St. Charles was found 87 days before departure, on average.
  • Book at least 1 week before departure in order to get a below-average price.
  • High season is considered to be April, May and June. The cheapest month to fly is August.

Reviews of the top 5 airlines serving Philadelphia to St. Charles

 
Need help choosing which airline to fly with from Philadelphia to St. Charles? 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.
7.9
SouthwestOverall score based on 4251 reviews
7.5Entertainment
8.6Crew
8.0Comfort
7.0Food
8.1Boarding
Airline reviews

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

8.0 ExcellentRussell, Dec 2025
SAN - OAK
Read more Southwest reviews

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

Still a fan of open seating. Flight was on schedule and arrived on time. The 737 MAX is very comfortable.

Airline travel is always too cramped to really be pleasant, but the cabin crew on this flight did a pretty good job of making up for it by putting on some music during boarding and sprinkling a few funny remarks into the safety briefing and announcements, and just generally being friendly and helpful. It definitely reminded me of why I prefer the in-flight experience on Southwest!

No delays and arrived to destination 30 min early. Staff was super friendly.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

It was rough. The staff was unprofessional, the choice of on board drinks terrible, it was cramped in space at every airport, they always ran out of overhead bin space so they pressured people to check bags for free or we couldn’t leave on the plane— so I did check my bag to help, and they nearly lost my bag. My bag did not arrive on the luggage belt, another man on my flight and I had to waste our time going to the baggage office to search for our bags. I would only fly southwest again if it was my last choice. Also, my flights were consistently delayed over and over again— at one point they straight up told us we were waiting for the pilot to arrive.

Crew could have been friendlier, maybe I'm spoiled by SW crews. In flight wifi was good. Would be nice to have more food offerings on a 4 plus hour flight

Had to get off plane from prior flight even though I had to reboard same plane to continue to my final destination.

Everything a cheap airline should be at normal airline rates.

Original flight was cancelled and when i was rebooked by the airline, they couldn't seat me in the same type of seat as I had originally booked (went from window/aisle to middle/middle and one was a bulkhead seat, and other wasn't in the same class)

Lady Pilot was perfect in every way wheels up to wheels down communication, professionalism, excellent on time departure and on time arrival, excellent communication! Fantastic job with Superb attitude!!

The food is terrible. The staff is wonderful. Comfort is good.

Left on time, a bit delayed due to headwinds most of the trip.

I fly Delta all the time, have Platinum Medallion status. But this route seems to have major problems with delays and seems to never leave on time! Have only taken it twice in the last two weeks, and each time it had delays of more than 1 hour... very disappointed!!!!

Good seats in Main cabin, excellent service and excellent landing

My flight was cancelled with no explanation after I had already cleared security. I was given 4 options to rebook, only one being non-stop like I had paid for. I grabbed it. It was 4 plus hours later and then took off even later. Biggest complaint is that I booked early and had an aisle seat. They gave me a "window" seat in front of the exit row, so the seat did not decline. I weigh all of 103 #s and it was tight for me! For what I paid, I feel I was kind of ripped off. I think they should have given me the empty comfort seat for the inconvenience. There was no apology nor any explanation as to why the flight was cancelled. My guess is it benefitted Delta in some way.

Very smooth, on-time, and pleasantly uneventful flight. The team at the gate and on board were professional and genuinely courteous. The pilot kept us well updated throughout, and both takeoff and landing were steady and enjoyable without any drama. Just a good, solid flight. Thank you! 💗

Staff was exceptional! Everyone was kind, professional and friendly making the trip very pleasant. Thank you!

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

Delays to take off and to leave the plane after landing added a lot of time to this flight.

The Phildalphia to Allentown portion was a BUS, not a plane. All was as expected.

Excellent - explanations were clear staff was nice and flight was comfortable

Flight was delayed not sure why no explanation given and no apologies either. Otherwise the flight was fine

Did not get the seat I selected and paid for.

Plane was delayed for 6 hours, at first by weather, which is understandable, but was further delayed with NO given reason for 2 1/2 hours more. We had no clue when we were going to depart actually until they opened the ramp. VERY POOR to ZERO COMMUNICATION!!!

Flight was delayed and after being in the airport for like seven hours, it was canceled.

Flight delays numerous times. Everytime we would get close to boarding it would be delayed again. Strung along the entire time.

Overall very good, only complaint I have is the crew from CLT to SAT could have collected trash sooner.

Above and beyond effort from this crew in a tough situation. So helpful and understanding. Thank you!

The seats are the most uncomfortable seats I’ve ever sat in. Don’t believe I’ll ever fly spirit again!!

Flight was canceled and instead of rescheduling at the gate we had to go out to the ticket counter. Unruly kids kicking the back of my rows chair with staff to inattentive to say something.

Customer feedback I sent to Spirited today: “I will never fly Spirit Airlines again and will work hard to convince my friends and family to boycott/avoid Spirit Airlines at all costs. I booked three seats for me and my 8 and 10 year old children on NK 1222 from Orlando to Kansas City for 12/7/25 leaving Orlando at 10:37AM. This itinerary was abandoned by Spirit and we were rebooked onto Spirit flight NK 213 leaving at 9:06PM without any notice. Then the nightmare really began. Flight 213 was delayed a total of 12 times, finally leaving at 6:35AM the following day. The gate was changed 5 times and our electronic boarding passes were invalidated at midnight. The worst part was that the 12 separate delays were incremental making it impossible to plan for accommodations for my family. My kids missed a day of school and barely slept under the harsh lights with lots of noise on the filthy airport floor. The customer service agent at Spirit Airlines told us we would be emailed a voucher for a hotel which never happened. I asked about it multiple times and it never arrived in my email inbox. This whole unfortunate situation could’ve been avoided if spirit had taken a realistic approach and delayed the flight from 9 PM until 6 AM from the beginning. My son gleefully deleted the Spirit app from my phone once we landed and we will never fly with Spirit again.”

Honestly horrible. The plane on the way back was delayed 6 times with no explanation on why. When I asked for a refund or some money back because I had to miss a day of work because of the desk, they told me no. Because of how poorly it was handled I will most likely never take spirit again

I love a flight without turbulence and you guys deliver It’d be nice to have comfier seats and maybe some inflight entertainment and snacks but that’s for Delta

This was my first time on a budget airline and I couldn't even sit down all the way because my knees would embed in the seat in front of me. I'm only 6' tall with a 32" inseam. There's no upside other than y'all are cheap. I'm glad it was only a 2 hour flight. Lesson learned! I get why everybody talks down on budget airlines. The staff was outstanding, the flight went as well as possible, great pilot, great boarding, smooth sailing. Zero chance I'll be back though.

Everything was smoothly and convenient! Just stay in this way!

Cancelled my flight and the earliest that they are willing give me for the next flight which was 3 days later on a weekday. Only accommodation they are willing to give was $30 airline credit that will expire in 1 year

Terrible Airline I will never fly that airline again. Shame on you for recommending them.

Flight was canceled, huge lines to get baggage returned. Most other airlines had delays but not widespread cancellations like Spirit.

Not clean and was told I would get a great seat and it was not great at all

Flight got delayed for 5 hours no good explanation was offered ;(

Horrible. I would never fly Frontier again. The booking process is tricky at best, but fraudulent in my opinion. Frontier customer service did nothing to rectify my purchase -- I ended up paying more than double what I could have gotten from other airlines and nearly triple what I thought I was buying from Frontier. Their booking practices are unfair to the consumer.

Delayed. Text notifications were slow. Not much information o what was happening. Boarding was slow and confusing. Wasn’t even offered water other flight. Had to ask. No entertainment at all. Felt like.a Greyhound bus.

When I wanted to check in 3 hours prior to boarding time, the employees mentioned “a little over an hour delay” so I waited for an hour then I went to go look for food in the terminal and most people from that flight were in the same area looking for food. Finally I decided after food to check to see if it’s anytime closer and now it’s 2 mins until boarding closes?! What are you kidding me? I didn’t receive anything via sms about boarding now nor via email or on the intercom. I luckily made it through, barely, and then there’s no room for my carry on mind you I’m in the very first row so I had to place my purse in one further row back and my carry on sections down. Not sure who pays for better seats to get your stuff placed all over the plane but that was the worst experience I’ve ever had flying with anyone.

Better than expected. Staff were friendly and nice on both flights.

There was no one at the counter to assist with our check in. The app didn’t work, so I arrived at the airport with time to check in and I couldn’t because no employees were there. When I finally got someone on the phone, it was inside the 60min rule and they said I could no longer check in and they could sell me another ticket. We had to scramble and pay an additional $800 for tickets and THEN AFTER (about 60 min from my original convo with customer service and 10min after original departure time) I had boarded my new flight, there was email saying my original flight from Frontier was delayed and leaving 2hr 50min later, but I STILL wouldn’t have been able to check in. Which means customer service should have been able to see it and let me check in because I was well within my check in time. When I call Frontier, they hang up on me. So their app didn’t work and they employees left and they take zero responsibility or assistance with their “customer service”

Terrible. Flight cancelled with no reasoning and no flights to rebook. Employees were useless and did nothing to help. Did not even know where to retrieve luggage from the cancelled flight. Flyers beware.

No fault of Frontier staff: plane was very late, reached Orlando at 1 am, took a while to get luggage. Weather, gov financial shutdown impact on TSA, air controllers seemed to have multiple flights backed up. Frontier staff seemed to cope as gracefully as possible. It did reassure me that I and my new hip could adapt to travel challenges. Food/entertainment were irrelevant to my trip.

Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.

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

Complete your trip to St. Charles with a hotel stay or car rental