$80 Find Cheap Flights from Seattle 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 Seattle to St. Charles departing on 10/27. 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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Cheap Flights from Seattle to St. Charles (SEA-STL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle 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 Seattle to St. Charles

Wed, Sep 3 - Tue, Sep 9
United Airlines Logo
7:00 am - 3:44 pmSEA-STL
6h 44m1 stop
United Airlines Logo
5:49 pm - 10:59 pmSTL-SEA
7h 10m1 stop
$180United Airlines
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Thu, Sep 25 - Mon, Oct 6
American Airlines Logo
10:11 am - 8:25 pmSEA-STL
8h 14m1 stop
American Airlines Logo
4:34 pm - 12:27 amSTL-SEA
9h 53m1 stop
$189American Airlines
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Tue, Aug 12 - Mon, Aug 18
Frontier Logo
6:25 am - 9:11 amSEA-STL
24h 46m1 stop
Frontier Logo
7:29 pm - 11:01 pmSTL-SEA
29h 32m1 stop
$192Frontier
Find Deal
Sat, Sep 20 - Sun, Sep 28
United Airlines Logo
7:00 am - 3:44 pmSEA-STL
6h 44m1 stop
United Airlines Logo
5:47 pm - 11:15 pmSTL-SEA
7h 28m1 stop
$208United Airlines
Find Deal
Thu, Sep 25 - Sun, Sep 28
Hawaiian Airlines Logo
6:03 pm - 11:59 pmSEA-STL
3h 56mnonstop
Hawaiian Airlines Logo
6:30 pm - 8:59 pmSTL-SEA
4h 29mnonstop
$249Hawaiian Airlines
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Wed, Sep 10 - Mon, Sep 15
Southwest Logo
7:00 am - 3:55 pmSEA-STL
6h 55m1 stop
Southwest Logo
2:25 pm - 4:45 pmSTL-SEA
4h 20mnonstop
$259Southwest
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Tue, Jul 29 - Tue, Aug 5
Delta Logo
11:59 pm - 10:33 amSEA-STL
8h 34m1 stop
Delta Logo
5:37 pm - 11:56 pmSTL-SEA
8h 19m1 stop
$269Delta
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Wed, Aug 6 - Sat, Aug 9
Southwest Logo
7:00 am - 5:55 pmSEA-STL
8h 55m1 stop
Southwest Logo
1:45 pm - 11:30 pmSTL-SEA
11h 45m2 stops
$274Southwest
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Thu, Jul 24 - Mon, Jul 28
Hawaiian Airlines Logo
12:46 pm - 6:35 pmSEA-STL
3h 49mnonstop
Hawaiian Airlines Logo
7:32 pm - 10:00 pmSTL-SEA
4h 28mnonstop
$289Hawaiian Airlines
Find Deal
Mon, Aug 4 - Wed, Aug 6
Alaska Airlines Logo
6:06 pm - 11:59 pmSEA-STL
3h 53mnonstop
Alaska Airlines Logo
7:32 pm - 10:00 pmSTL-SEA
4h 28mnonstop
$323Alaska Airlines
Find Deal
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Good to know

Low seasonJanuary
High seasonJuly
Cheapest flight$80
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly with an average 16% increase in price.
Flight from Seattle to St. Louis

When to book flights from Seattle to St. Charles

Are your dates flexible? Find out the best times to travel from Seattle 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

Flights from Seattle to St. Charles: the best tips from KAYAK users' own experiences

Insights shared by verified travelers who flew the route from Seattle to St. Charles 
Verified travelerFlew with Alaska AirlinesSEA-STLJul 2025
Give yourself extra time. Love the self check in options.
Verified travelerFlew with Alaska AirlinesSEA-STLFeb 2024
Be sure to measure your wheels for carry on my luggage was the correct size but the wheels made it over so had to check my bag wasn't happy about that since you have to pay for checked should at least get one free.

FAQs for booking flights from Seattle to St. Charles

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

    When flying out of Seattle you’ll be using Seattle/Tacoma Intl. 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 Seattle to St. Charles take?

    Direct flights cover the 1,704 miles separating Seattle and St. Charles in about 3h 49m.

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

    17 direct flights run between Seattle and St. Charles on a daily basis. On average, there are about 120 departures each week.

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

    Consider leaving on a Wednesday and avoid Sundays if you are looking for the best rates. For your return to Seattle, you’ll find the best rates on Thursdays and the most expensive ones on Sundays.

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

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Charles from Seattle 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 Seattle 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 Seattle with another airline.

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

    In the last 72 hours, the cheapest one-way ticket between Seattle and St. Charles found on KAYAK was with Frontier for $80. United Airlines offered a round-trip connection from $180 and American Airlines from $189.

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

  • There is no airport in St. Charles. Instead, you’ll be flying into St. Louis Lambert Airport when flying between Seattle and St. Charles.
  • The cheapest flight from Seattle to St. Charles was found 52 days before departure, on average.
  • Book at least 2 weeks before departure in order to get a below-average price.
  • High season is considered to be November, December and January. The cheapest month to fly is September.

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

 
Need help choosing which airline to fly with from Seattle 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.
8.0
Alaska AirlinesOverall score based on 10000 reviews
8.1Boarding
7.1Food
8.5Crew
7.8Comfort
7.1Entertainment
Airline reviews

Seats very comfortable and legroom appreciated. All in all, it was a great experience.

10.0 ExcellentMatt, Jul 2025SEA - ATL
Read more Alaska Airlines reviews

Seats very comfortable and legroom appreciated. All in all, it was a great experience.

Original flight was canceled, and the automatically booked second flight was immediately delayed. I arrived about 4 hours later than planned with only a $12 meal voucher that didn't fully cover a sandwich at airport prices.

I was expecting better service from Alaska Airlines. I registered for assistance since I have a disability. The terminal in Seattle, WA was very unprofessional and at times rude. The BWI location was the exact opposite. I will NOT consider Alaska Airlines for future flights.

It was very good and comfortable, Crew was also great

The flight was delayed almost an hour. No wifi on flight.

Good experience, although it was a little cramped being a tall person. Otherwise everything went smoothly and professionally though

Delay of more than 3 hours I didnt recieve neither a voucher for food Attention disaster

Flight was 1:20 later than booked & I never received notice. At airport way too early. Couldn’t hear announcements on PA system. Crew fine. Retrieving luggage fine. Overall experience not good.

I will never take a red-eye flight again. Crying babies. Complete full flight. Could not get comfortable. Not fun.

Flight was OK, landing not good, boarding was ridiculous. Flight was to load at gate n11 25 minutes before boarding time it was changed to s5 which is 3 tram connections on the other side of the airport, I'm handicapped and even getting a sky cap took 10 minutes needless to say just made it to boarding only because it was delayed. I did learn a valuable lesson don't show up for flight 2 hours early.

Delayed flight. Nicest crew member was a SW pilot flying seated next to me who kindly move to seat the final passenger. Flight extra delayed. My cup of refreshment of ginger ale was so packed with ice it was literally 2 sips.

For my birthday trip this was my second time ever flying, this trip was the best.

after landing, we stay 2 hours on the taxi way before reaching the gate The airline and the crew were good though

No trays in our seats, we sat in first row, purchased a business class fare. Had to hold our drinks and snack in our hands. No plugs for our cell phones. Had to pay for it a drink cocktail each. Seats so uncomfortable.

Flight wasn’t even full, but too many carry-ons caused us to run out of bin space. New bag fee has folks who would usually check their bags carrying on. Watching Southwest morph into Spirit/Frontier is so sad to watch

Sat on tarmac for 2 hours and then missed my connecting flight

First time traveling on Southwest since bag fees were implemented. Usual good service. Just more expensive now.

Everything was on time. I was disappointed by the front section female, African American flight attendant. I did not see her name tag or would have identified by name not race. As passengers moved to the bathroom early in flight, she would say with a disdainful tone “I have to say the seat belt light is on” then go back to her book. Better trained flight attendants say something like be careful the seat belt light is on.

Cluster mess boarding. Can't wait for SWA reserved seating. Internet didn't seem to work on the plane.

Flights delayed by 4-6 hours. Boarding was a mess and unclear. Bags were not at arrival airport and had never even been put on the plane. No idea when I’ll get them. Don’t fly into Denver!

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

My flight was extremely cold. I had a jacket and a cover was left in each seat. The cover was extremely thin and I have a disability, fibromyalgia and arthrithis and AC air is the worst. I closed my vent and my husbands vent and it still was frigid. I asked the attendant if I could get another cover and she quickly almost dismissively and totally unconcerned stating, (I quote) (one per chair) and walked off so quickly that I didn't get a chance to explain to her that I literally have adisability. I didnt want to make a seen so I set on that flight for over 5 hours in pain, joints locking up and extremely uncomfortable. When my fibromyalgia flares up my joints not only ache but they will lock up also and it takes me days to get back to my regular self even though I take medication for it. I felt like it would not have hurt anyone at all for her to just give me an extra cover because I'm sure they have all types of medical issues in people that fly every day.

After all the weather issues at least they got me to my destination the next day

My flight was canceled after being rescheduled for four days canceling my trip. Kayak and everyone affiliated with it I.e the airlines, and just fly have been excruciating to deal with. My trip to visit family had to be canceled as there was no way to make it. I am furious at all of you.

They delayed our flight because of bad weather in NY which was completely understandable. Then they cancelled our flight and a later flight that evening. The earliest we could fly was the next morning. We ended up buying last minute tickets on another airline and made it home slightly delayed but safely that evening. Delta kept saying it was weather related but if that was the case how did we make it back on another airline? The weather in NY was cloudy but not bad.

From Atlanta to Savannah - flight connection was way to short (we weren't even late landing ) and flight was already boarding when we landed - we were told we were the last on board and so we had to gate check our bags. Once we got on the plane, there were at least seven open bag spots so that was unnecessary delay. There should be better communication between the gate agent and the crew.

Crew was excellent. Comfort seats not as nice as other kinds of planes.

Not a "Delta" issue, but a JFK issue: We booked a connecting flight with 3 1/2 hours between to clearn immigration and customs. Our inbound flight (BCN to JFK) was on the taxiway 45 minutes which ate into our layover time. Immigtration was insanely quick with the CBP MPC app; however, clearing TSA (again, after we were ALREADY cleared in Spain on the inbound international flight) took over 95 minutes. This left us with 10 minutes before boarding the connecting flight (JFK to SAN) to walk to the far end of Terminal 4 and try to find food. We didn't find any food that could promise to serve us in under 10 minutes so we boarded the Delta flight after coming off a plance and an 8-hour flight knowing that we wouldn't be served any food on the next 5 1/2 hour flight. I feel like Delta needs to put pressure on the JFK TSA to open more screening stations (by our count, we saw only 5 scanners open and a line of - as we said - over 90 minutes. The insult is that we WERE ALREADY SCREENED through TSA, but as you come off one flight into the USA, you have to go through the whole process again. It seems like if you have a connecting flight, there should be a way to pass through immigration and customs without needing to return through TSA.

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

I was unable to get a check im and get a boarding pass. I tried at the desk of the flight operator Alaska, was told to go to Hawaiian and almost had to go back to Alaskan. In the end inwas told to go thru security and directly to the gate without checking in. It would have been more helpful to have the details rather than walking all over the terminals trying to check in.

Nothing. Fare didn’t allow seat allocations. So we were stuck in the middle . Not good for 77 to 80 year olds. I was stick on plane. Taken off the plane before take off and ground staff told me to google where a hospital was to get a clearance to travel again. Left on own at airport ti fend for our selves. Also was charged for baggage, also I was not aware. I think booking through a third party, such as yourselves, doesn’t allow any for considerations when allocating seats.

I booked on Hawaiian and was bumped to an American airline flight in a different terminal. I was traveling with my two kids and told to take an air train to check my baggage in. We were given the last three seats in front of the toilet. Never flying Hawaiian again. Totally unreliable.

Good except that I couldn’t change seat and made me wait untill I checked in

The middle name gave us so much issue at check in we had done middle names when booking but Hawaiian/Alaska don’t recognize the middle names and gave us problems at check in. We have never experienced that before.

Everything was great except for the delayed flight times (it was delayed twice).

I was booked thru Hawaiian Airlines (HA) on Kayak in February. I got 2 confirmation emails from Hawaiian Airlines in February. Even though the flight ticket informed me the flight was marketed thru HA and operated by Alaska Airlines (AA), I was never given any confirmation codes or anything from Kayak or AA to check into my flight online ahead of time. They also couldn't find the HA flight number I was given on their website and was told my flight did not exist unless I searched thru the AA website for flight details that was similar to the info HA gave me. The only way to check into my flight and make sure the flight still existed required me to get there 4 hours early. When I arrived at the airport, HA desk told me to go to AA desk. First AA desk redirected me to another desk, second AA desk told me to find someone with an iPad, and finally the iPad rep was able to help me. I also had to chat with AA reps online the night previous to my return trip because the same issue occurred.

Traveling with my 90 year old mother, the boarding process was great, the gate crew was very helpful and friendly. One of the flight attendants was kind enough to assist her to and from the restroom mid-flight and cater to any requests she had. I wish I flew Hawaiian Airlines more often, it was a great trip!

I did not board neither one of my flights because It got delayed and I had to be at my destination at a certain time

We were delayed at the SD gate for close to an hour before we were allowed to depart for SJ. Reason given was inadequate ground crew to move the plane from the gate.

AA re-routed flight from HNL to LAX due to delay. My group of 3 with reserved seats in row 9 was broken up, with one assigned to a middle seat, another in the last row of the plane. Not happy. No explanation to the delay. No apologies. No compensation. Would have been nice to be offered an Admiral Club admission or a voucher for the extra 3 hours of layover in LAX. Could not hear the boarding gate announcements in LAX. Adjacent gate was boarding at the same time. Loud speakers were competing against each other. Barely made my boarding group.

Boarding gate in Honolulu was staffed with a great clerk with a soothing voice despite the flight delay of over an hour. Flight attendants in the plane were all grumpy, not pleasant looking bunch. Their sour attitude showed throughout the flight. Inly able to get a select few movies started. Most of the movie links in the “free entertainment” did not work.

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

The flight delay in Dallas created a domino effect that impacted all connecting flights, leading to an increase in the number of connections. As a result, I missed my flight from Casablanca to Marrakech due to the tight turnaround when landing in Casablanca. CMN Airport was understaffed; only one employee was available to assist passengers while others just stood by and watched. It was an extremely frustrating situation. Many passengers were crying and banging their hands on the counter while talking to customer service representative Allabough. Unfortunately, Allabough couldn’t change my flight in the system. At the same time, I was on the phone with an American Airlines customer service representative named Solomon, who said he couldn’t make the change either. So, I decided to take an ONYA Voyages train from Casablanca to Marrakech to reach my destination on Friday, June 26. It turned out to be an unpredictable trip.

The flight was fine and the crew awesome. The problem is ORD and AA. Computers went down, ORD fell apart and a 40 min flight turned into a 3 hour trip. Guess the answer is to not try and fly to ORD after noon. But, as I said, crew was awesome and did everything they could to lesson the flight time.

Almost a 6 hour flight and the only food option is a cheese plate… and chips. Also how is it there are no options for texting on American. I’ll be going back to delta and united.

This flight never occurred because AA couldn’t get their act together.

Terrible. Cancelled my original flight. It made getting a boarding pass difficult. The AA employee (in a loud voice, so everyone around could hear) griped at me for not getting a boarding pass 24 hours before. I asked how I was supposed to do that when I had no idea what flight I was going to be on. She said (loudly), “Talk to AA customer service, not me!” I could certainly tell serving customers was not important to her. Our new flight was set to a completely different city. We had to change our rental car, and the price went way up. It took 2-1/2 hours to get checked in. By then our new flight had left. We ended up on stand by and had to split up the family to get to our destination. It cost us the whole first day of the trip. AA needs to employ people who actually care about doing a good job. I suppose those people are getting harder to find, but atleast try.

Am still mad at American airlines. You should know it's us travel nurses who are your customers and you treat us like nonsense it's not ok. American airlines took my money, no refund for whatsoever. A trip that was of 466 and I paid 466 and 833 then they chose for me where to sit and refund my seat choices and gave me expensive seats for 79 USD. Kayak doesn't help at all after booking you are on your own. Skyscanner is better

This was a horrible experience. For a first class experience, my chair was held together by 3M tape - and I have a photo. The crew weren’t very attentive, somewhat dismissive and forgot my drink and snack, the chair reclined about 3 inches on a 6-hour cross country flight. I was also not informed that there was no lounge available in Newark airport because of renovations, so all around this was one of the worst experiences and I would actively avoid both American and Alaska Air going forward.

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