SEA - STL

$114 Find Cheap Flights from Seattle to St. Louis - Compare and Save

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Everything you should know

Cheapest round-trip
$227
Typical prices: $313-$605
American Airlines
Fri 2/23Fri 3/2
SEA - STL • 1 stop
Cheapest non-stop
$467
Typical prices: $348-$621
Alaska Airlines
Wed 12/12Mon 12/17
SEA - STL • Non-stop
Advice from real travelers
At Seattle, Alaska’s self check-in can save time; arrive early for this route.
On Alaska, measure carry-on wheels carefully or you may pay to check bags.
Expert advice
+1
Expert advice
+1
Nonstop flights
You can fly direct with Alaska Airlines. Average duration is 3h 54m
Direct flights
+1
Direct flights
+1
When to book
in advance
Our data shows that travelers who book at least 15 weeks in advance save around 59% compared to booking last minute.
Insights
Insights
When to travel
Cheapest • 48% price drop
Most popular
Good to know
+1
Good to know
+1
Top layover airports
Cheapest • Avg $240 (round-trip)
Shortest trip • 6h 35m (one-way)
Insights
Insights
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We hope you love your trip to St. Louis!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Seattle to St. Louis (SEA-STL)

 
Discover the best prices for you by selecting your travel dates on KAYAK.

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

Tue, Feb 23 - Tue, Mar 2
American Airlines Logo
6:13 am - 5:19 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
9h 06m1 stop Chicago O'Hare Intl
American Airlines Logo
7:31 am - 2:21 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
8h 50m1 stop Chicago O'Hare Intl
$227American Airlines
Sat, Dec 5 - Sat, Dec 12
American Airlines Logo
3:28 pm - 12:02 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
6h 34m1 stop Chicago O'Hare Intl
American Airlines Logo
5:23 pm - 12:47 amSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
9h 24m1 stop Chicago O'Hare Intl
$227American Airlines
Wed, Dec 2 - Wed, Dec 2
Southwest Logo
5:40 am - 2:50 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
7h 10m1 stop Phoenix Sky Harbor Intl
Southwest Logo
4:40 pm - 11:35 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
8h 55m1 stop Chicago Midway
$227Southwest
Tue, Jan 12 - Sat, Jan 23
Southwest Logo
5:40 am - 4:35 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 55m1 stop Phoenix Sky Harbor Intl
Southwest Logo
5:35 am - 1:00 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
9h 25m1 stop Chicago Midway
$227Southwest
Tue, Feb 23 - Tue, Mar 2
Delta Logo
11:25 am - 9:41 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 16m1 stop Salt Lake City
Delta Logo
2:15 pm - 6:30 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
6h 15m1 stop Salt Lake City
$227Delta
Tue, Dec 1 - Wed, Dec 2
Delta Logo
1:25 pm - 9:28 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
6h 03m1 stop Salt Lake City
Delta Logo
5:20 pm - 11:53 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
8h 33m1 stop Minneapolis St Paul
$227Delta
Wed, Dec 9 - Tue, Dec 15
United Airlines Logo
5:05 am - 12:53 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
5h 48m1 stop Denver Intl
United Airlines Logo
10:50 am - 4:18 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
7h 28m1 stop Chicago O'Hare Intl
$227United Airlines
Tue, Jan 12 - Sat, Jan 16
United Airlines Logo
7:00 am - 5:50 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 50m1 stop Chicago O'Hare Intl
United Airlines Logo
5:06 pm - 10:45 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
7h 39m1 stop Chicago O'Hare Intl
$227United Airlines
Fri, Nov 20 - Tue, Nov 24
Frontier Logo
4:37 pm - 11:03 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
16h 26m1 stop Denver Intl
Frontier Logo
5:15 pm - 12:37 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
21h 22m1 stop Las Vegas Harry Reid Intl
$275Frontier
Mon, Dec 7 - Fri, Dec 11
Frontier Logo
4:58 pm - 12:12 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
29h 14m2 stops Denver Intl Orlando
Frontier Logo
7:54 pm - 3:43 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
21h 49m1 stop Denver Intl
$294Frontier
Booking Insights

Price, demand and travel trends for Seattle to St. Louis flights

Use KAYAK data on prices, travel dates, airlines and seasonal trends to compare options and book flights with more confidence.

How much is a round-trip flight from Seattle to St. Louis?

Round-trip flights from Seattle to St. Louis typically range from $313 to $605. The lowest price found in the past 5 days was $227, on American Airlines.

What's the cheapest day of the week to fly from Seattle to St. Louis?

Based on deals KAYAK users found in the last 12 months, Tuesday is the cheapest day of the week to fly from Seattle to St. Louis. It’s 15% cheaper than the average day, while Sunday is the most expensive, with prices 40% higher.

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

•January is the cheapest month to fly from Seattle to St. Louis at $232 round-trip.
•December ($543) and July ($532) are the most expensive months.
•The price difference between flying in the cheapest and most expensive months is 134% on average.
This is based on KAYAK aggregated and averaged internal data over the past 12 months.

When are flights from Seattle to St. Louis the cheapest?

Flights from Seattle to St. Louis are cheapest 15 weeks before departure. Booking in this window typically costs about 59% less than the average last-minute fare (within 2 weeks of the flight), based on KAYAK data.

Expert advice

Expert advice for your flight from Seattle to St. Louis

 
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

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.

Harriet Baskas

Harriet Baskas

Expert on SEA

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.

Key details for Seattle to St. Louis flights

Low season

September

Cheapest flight

$114
Beat the crowds with an average 35% drop in travelers.
The most popular month to fly with an average 62% increase in travelers.
One-way flight from Seattle to St. Louis

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

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

Insights shared by verified travelers who flew the route from Seattle to St. Louis 
Verified travelerFlew with Alaska Airlines-Jul 2025
Give yourself extra time. Love the self check in options.
Verified travelerFlew with Alaska Airlines-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.

Your Seattle to St. Louis flight questions, answered

Find helpful answers about this route, including flight times, airports, airlines and booking tips.

  • What are the earliest and latest flights from Seattle to St. Louis?

    These are the earliest and latest flight times available from Seattle to St. Louis:

    • Earliest: departs at 8:22 am and lands at 12:16 pm
    • Latest: departs at 6:08 pm and lands at 10:02 pm.

    The flight takes about 3h 54m.

  • What cabin classes can I book on flights from Seattle to St. Louis?

    Two cabin classes are available on flights from Seattle to St. Louis:

    • Economy Class
    • First Class

  • How long is a flight from Seattle to St. Louis?

    A nonstop flight from Seattle to St. Louis takes 3h 54m, covering 1,704 miles.

  • Do I need a passport to fly from Seattle to St. Louis?

    No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID or another TSA-accepted form of identification.

  • How much should I expect to pay for a Seattle to St. Louis flight?

    Round-trip flights from Seattle to St. Louis range from $313 to $605, with an average of $447 over the past 12 months. Anything below $313 counts as a good deal.

  • How expensive are last-minute Seattle to St. Louis flights?

    Last-minute fares on this route (booked within two weeks of departure) run 45% above the $447 route average. Book 15 weeks before departure for the lowest fares.

  • How much can I save by taking a layover when flying from Seattle to St. Louis?

    On this route, layover flights are cheaper than nonstop options on average. Layover fares average $240 round-trip via Chicago Midway (MDW), compared to $472 for nonstop.

  • What is the standard checked-bag allowance on flights from Seattle to St. Louis?

    There is no standard. Checked-bag policies vary by airline on this route. Most carriers charge $40–$100 for the first checked bag in economy. Premium fares and elite-status bookings typically include a free checked bag.

  • Which aircraft model is used most often on flights from Seattle to St. Louis?

    The Boeing 737 family is used most often on this route, operated mainly by American Airlines. Other aircraft seen on the route include Boeing 737-800 Passenger/BBJ2 (winglets) variants.

  • How are flight departures from Seattle to St. Louis spread across the day?

    Morning is the busiest departure period on Seattle to St. Louis flights, with 50% of flights leaving in that window. Evening departures account for 50%, afternoon flights for 0%, and night flights for 0%.

  • Have flight prices from Seattle to St. Louis changed much recently?

    Yes. Based on fares seen in the past 5 days, round-trip prices on this route showed a wide range, from about $227 to $1,898. That means the highest observed fare was about 8x higher than the lowest one.

  • Which airlines offer Wi-Fi on Seattle to St. Louis flights?

    Alaska Airlines is the only airline on the Seattle to St. Louis route offering in-flight Wi-Fi. Pricing depends on fare class.

  • How are flight prices from Seattle to St. Louis looking right now?

    One-way fares from Seattle to St. Louis are currently lower than usual. Average one-way flight prices are about $116, which is 56% below the typical average for this route.

  • What car rental options are available at Lambert-St Louis Airport (STL)?

    Lambert-St Louis Airport (STL) hosts 5 major car rental companies, with daily rates averaging $78 for economy cars. Top options include:

    • Hertz
    • Budget
    • Alamo
    • Enterprise Rent-A-Car
    • Payless

  • Which airports can I use when flying from Seattle to St. Louis?

    Flights from Seattle to St. Louis usually depart from Seattle/Tacoma Intl (SEA) and arrive at Lambert-St Louis (STL).

  • Which airports do connecting flights from Seattle to St. Louis pass through?

    One-stop flights from Seattle to St. Louis most commonly connect through:

    • Denver Intl (DEN) - 40% of one-stop connections
    • Salt Lake City (SLC) - 21% of one-stop connections
    • Chicago O'Hare Intl (ORD) - 12% of one-stop connections
    • Dallas/Fort Worth (DFW) - 10% of one-stop connections

  • Can I save money by using flexible dates for flights from Seattle to St. Louis?

    Yes. Flexible dates can save you up to 40% on flights from Seattle to St. Louis. Tuesday is the cheapest departure day at $380 round-trip on average, while Sunday is the most expensive at $627, a difference of $247.

    KAYAK's flexible dates feature shows options up to 3 days before and after your selected dates, making it easier to compare nearby fares.

  • What airlines fly from Seattle to St. Louis?

    Only Alaska Airlines operates flights between Seattle and St. Louis.

  • How much time can I save by choosing a different layover airport from Seattle to St. Louis?

    Flying via Salt Lake City (SLC) gives the shortest average 1-stop total travel time at 6h 35m, compared with 6h 53m via Minneapolis St Paul (MSP) and 7h 25m via Chicago O'Hare Intl (ORD).

  • What is the time difference between Seattle and St. Louis?

    St. Louis is 2 hours ahead of Seattle (Central Time vs Pacific Time). Plan for the time shift when scheduling connections or first-day activities.

  • What popular places can I visit in St. Louis?

    Some of the most popular sights in St. Louis are Busch Stadium, Enterprise Center and America's Center Convention Complex. These are among the most viewed places in St. Louis on KAYAK.

  • Which airlines offer extra legroom and free seat selection on Seattle to St. Louis flights?

    Among airlines operating Seattle to St. Louis flights:

    • Alaska Airlines: offers extra legroom; offers free seat selection
    • American Airlines: offers free seat selection
    • Southwest: offers free seat selection

    Extra legroom and free seat selection availability depends on fare class and route.

  • Which airlines include bags at no extra cost on Seattle to St. Louis flights?

    Here are some options for this route, based on selected ticket types and cabin classes:

    • Alaska Airlines: a cabin bag and a checked bag in Economy Class
    • American Airlines: a cabin bag in Economy Class class
    • Southwest: a cabin bag in Economy Class class

    Bag allowance can vary by ticket type, cabin class, route and airline, so always check the fare details before booking.

  • What are the options to connect to downtown St. Louis from STL Airport?

    Travelers can take MetroLink, use a bus or rent a car to reach downtown St. Louis from STL Airport. MetroLink is a light rail system with stations at both STL Airport terminals. Rental cars are available from Alamo, AVIS, Budget, Dollar, Enterprise, National, Payless and Hertz.

  • Are there kid-friendly amenities on flights from Seattle to St. Louis?

    Yes. American Airlines offers on-demand, kid-friendly entertainment options on flights from Seattle to St. Louis. It provides free high-speed Wi-Fi on most domestic and select international flights for AAdvantage members, along with free streaming entertainment, including TV shows and music, on select flights. Games are also available on seatback screens on select flights.

Your guide to booking Seattle to St. Louis flights

Get tips on when to book, when to fly and what to know before your trip.
  • If your dates are flexible, aim for a Tuesday departure and avoid flying on Sunday. On this route, Tuesday flights average $380, about $247 less than Sunday fares (39% savings) based on the last 12 months.
  • For the best chance at a low fare, aim to book around 15 weeks before you fly. On this route, that window historically saves about 59% versus last-minute pricing (KAYAK booking data, last 12 months).
  • If you can choose when to travel, plan your Seattle to St. Louis trip for January. Fares historically average $232 round-trip in that month - typically $311 less than the most expensive month, which is December (based on the last 12 months).
  • If you have the time, taking a 1-stop flight through Chicago Midway Airport (MDW) can be cheaper than flying direct. The cheapest layover option averages $240 round-trip on this route - about $231 less than direct flights (based on the last 12 months).
  • If you're arriving late at night and need somewhere to stay, check out these hotels close to Lambert-St Louis Airport.

    • Renaissance St. Louis Airport Hotel
    • Drury Inn & Suites St. Louis Airport
    • DoubleTree by Hilton St. Louis Airport
  • If you're flying to St. Louis, use Seattle-Tacoma International Airport (SEA) as your departure airport. You can get there from the city center and downtown Seattle by taxi, bus or airport shuttle, with several lower-cost transportation options available.

Prefer to fly direct from Seattle to 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 direct 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 direct flights

More options for your flight from Seattle to St. Louis

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