SEA - STL

Find cheap flights from Seattle to St. Louis

1 adult
1 adult, Economy, 0 bags

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 Seattle 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 Seattle to St. Louis, as well as popular online travel agencies
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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.
No expert advice available for this route.
Measure carry-on wheels to avoid extra fees.
User tips
User tips
User tips
User tips
Direct flights
Every day
You can fly direct with Alaska Airlines. Average duration is 3h 56m
Direct flights
Direct flights
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Direct flights
Direct flights
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When to book
4 weeks
in advance
Our data shows that travellers who book at least 4 weeks in advance save around 50% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
January
Cheapest • 35% price drop
May
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
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KAYAK searches hundreds of sites at once to find you the best travel deals.
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$ 325 (return) on average. On the other hand, the most expensive months are December and March, where the average cost of round-trip tickets is C$ 717 and C$ 591 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$ 428 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 4 weeks before departure, which saves you about 50% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 26 weeks before departure.

Find deals

Good to know

Low seasonJanuary
Best time to beat the crowds (35% less expensive on average)
Most popular time to fly (12% 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, Hawaiian Airlines, American Airlines, and Delta 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.

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

  • Looking for a cheap flight? 25% of our users found flights on this route for C$ 381 or less round-trip.

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

Alaska Airlines

Tuesday

Alaska Airlines

Alaska Airlines

Wednesday

Alaska Airlines

Alaska Airlines

Thursday

Alaska Airlines

Alaska Airlines

Friday

Alaska Airlines

Alaska Airlines

Saturday

Alaska Airlines

Alaska Airlines

Sunday

Alaska Airlines

Alaska Airlines

See more nonstop flights

Direct returns

Lambert-St Louis to Seattle/Tacoma Intl

Monday

Alaska Airlines

Alaska Airlines

Tuesday

Alaska Airlines

Alaska Airlines

Wednesday

Alaska Airlines

Alaska Airlines

Thursday

Alaska Airlines

Alaska Airlines

Friday

Alaska Airlines

Alaska Airlines

Saturday

Alaska Airlines

Alaska Airlines

Sunday

Alaska Airlines

Alaska Airlines

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 12072 reviews
8.5Crew
7.8Comfort
7.0Food
7.0Entertainment
8.1Boarding
Airline reviews

Departing flight for our weekend trip was cancelled due to weather which meant our return flight was useless. The whole thing was difficult to get support through but Alaska did recover and was able to reimburse us for the flights yesterday. For some reason, Kayak was not kept in the loop, adding to the confusion.

2.0 MediocreDavid, Mar 2026
SEA - STS
Read more Alaska Airlines reviews

Departing flight for our weekend trip was cancelled due to weather which meant our return flight was useless. The whole thing was difficult to get support through but Alaska did recover and was able to reimburse us for the flights yesterday. For some reason, Kayak was not kept in the loop, adding to the confusion.

i canceled my return flight package with Alaska Airlines. Customer Service was excellent and assisted me to cancelled both of our reservations and returned the payment in full. that is excellent service and understanding and empathy of the customers' needs. i like Alaska Airlines and recommend AS to everyone.

Never got on because the airline sent the WRONG plane to take us on our first leg of the trip so we missed ALL connecting flights. No help available from anyone at the airline…

The crew inside the airport for Alaska was rude, lazy and incompetent

The flight was extremely smooth, and so was the landing. Great piloting.

Plane was clean, staff was professional and flight was on time. No built in tv was still ok, as programs were offered that could synch to smart phones.

J was in the ER x 3...3 protruding discs...contacted Alaska many many days prior to cancel and request a refund or a credjt.. they only gave me 50 % credit....outrageous seeing how i have a doctors letter....just plain inhuman. AI sucks!

The flight was too short. No snacks or drinks offered.

The flight attendant was friendly and attentive. Although our interaction was brief—- it made a difference. The crew was upfront about turbulence. I like the Maui pretzels.

Everything was good. Please have a wheat free option for snacks in the future.

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)