SEA - STL

Find cheap flights from Seattle to St. Louis – Compare and Save

1 adult
1 adult, Economy, 0 bags

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Everything you should know

Advice from real travellers
AI-powered summary based on content written by KAYAK users. AI can make mistakes.
At Seattle, Alaska's self check-in can save time; arrive early for smoother departure.
Measure carry-on wheels carefully; oversize bags may be checked for a fee.
User tips
User tips
User tips
User tips
Direct flights
Every day
You can fly direct with Alaska Airlines and Southwest. Average duration is 3h 55m
Direct flights
Direct flights
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Direct flights
Direct flights
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When to book
3 weeks
in advance
Our data shows that travellers who book at least 3 weeks in advance save around 38% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
January
Cheapest • 42% price drop
May
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
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We hope you love your trip to St. Louis!
Flight Deals
Booking Insights
Flight Deals

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

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

Multiple Airlines Logo
SEA
-
STL
4413 kmmulti-stop
Multiple Airlines Logo
STL
-
SEA
4413 kmmulti-stop
Multiple Airlines
Booking Insights

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

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

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle 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 Seattle to St. Louis is January, where tickets cost C$ 334 (return) on average. On the other hand, the most expensive months are December and July, where the average cost of round-trip tickets is C$ 755 and C$ 715 respectively.

Can I save money by flying with a layover from Seattle 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 C$ 740 on average.

How far in advance should I book a flight from Seattle 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 Seattle 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 Seattle to St. Louis, you should book around 3 weeks before departure, which saves you about 38% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 18 weeks before departure.

Find deals

Good to know

Low season

January
Best time to beat the crowds (42% less expensive on average)
Most popular time to fly (4% more expensive on average)

When to book flights from Seattle to St. Louis

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

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

Insights shared by verified travellers who flew the route from Seattle to St. Louis 
Learn how KAYAK collects reviews and tips from users.
Verified travelerFlew with Alaska Airlines
SEA
-
STL
Jul 2025
Give yourself extra time. Love the self check in options.
Verified travelerFlew with Alaska Airlines
SEA
-
STL
Feb 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. Louis

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

    Alaska Airlines, JetBlue, Delta, and Hawaiian Airlines offer inflight Wi-Fi service on the Seattle to St. Louis flight route.

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

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

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

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

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

    There are direct flights from Seattle to St. Louis on a daily basis.

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

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Louis 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. 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 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. 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 Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Prefer to fly direct from Seattle to St. Louis?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Seattle/Tacoma Intl to Lambert-St Louis.
Find which airlines fly direct from Seattle/Tacoma Intl Airport to Lambert-St Louis Airport, which days they fly and book direct flights.

Direct departures

Seattle/Tacoma Intl to Lambert-St Louis

Monday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Tuesday

Alaska Airlines

Alaska Airlines

Wednesday

Alaska Airlines

Alaska Airlines

Thursday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Friday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Saturday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Sunday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

See more nonstop flights

Direct returns

Lambert-St Louis to Seattle/Tacoma Intl

Monday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Tuesday

Alaska Airlines

Alaska Airlines

Wednesday

Alaska Airlines

Alaska Airlines

Thursday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Friday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Saturday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

Sunday

Alaska Airlines,Southwest

Alaska Airlines,Southwest

See more nonstop flights

Reviews of the top airline flying from Seattle to St. Louis

 
See real verified KAYAK customer reviews for airlines flying from Seattle 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 Seattle 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.
7.9
Alaska AirlinesOverall score based on 12728 reviews
7.8Comfort
7.0Entertainment
8.5Crew
7.0Food
8.1Boarding
Airline reviews

SeaTac airport hottible No signage to tell you where to go Took one and half hour to make to gate after being dropped at airport HORRIBLE LOTS OF yelling at patrons EXTREMELY HORRIBLE AND SCARY!

2.0 MediocreAnonymous, Sep 2025
SEA - STL
Read more Alaska Airlines reviews

SeaTac airport hottible No signage to tell you where to go Took one and half hour to make to gate after being dropped at airport HORRIBLE LOTS OF yelling at patrons EXTREMELY HORRIBLE AND SCARY!

Late boarding, but the flight was smooth and the crew was accommodating.

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

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.

Leg room was quite OK. Customer service from the crew was spot on.

The Alaska airlines flight attendants were great. Boarding went smoothly. The cabin was comfortable intitially, and seemed stuffy later. I tried to open the vents but they were not very powerful to cool our seating down. Ride was smooth. They left the gate early and arrived early. The pubic address used by attendants was scratchy. No, it wasn’t their voices it was their system.

I was trying to switch from a middle seat to an aisle seat which usually I am able to. They did not want to switch seats for me and we're trying to charge me $80. I was sitting next to a bunch of kids that were really loud. Thankfully, I was seating between two very kind people.

service was good. flight attendants were friendly. flight was smooth.

Great. They got us on an earlier flight. Really appreciated that

The flight was bumpy and hard landing. No in-flight entertainment onboard couldn't connect to wifi.

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

Information on your arrival and departure airports

Seattle (SEA)
St. Louis (STL)