STL - SEA

$104 Find Cheap Flights from St. Louis to Seattle - Compare and Save

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Everything you should know

Cheapest round-trip
$196
Typical prices: $289-$517
Frontier
Fri 11/9Sun 11/11
STL - SEA • 1 stop
Cheapest non-stop
$281
Typical prices: $312-$540
Alaska Airlines
Sat 10/13Sat 11/3
STL - SEA • Non-stop
Nonstop flights
You can fly direct with Alaska Airlines and Southwest. Average duration is 4h 30m
Direct flights
+1
Direct flights
+1
When to book
in advance
Our data shows that travelers who book at least 7 weeks in advance save around 42% compared to booking last minute.
Insights
Insights
When to travel
Cheapest • 41% price drop
Most popular
Good to know
+1
Good to know
+1
Top layover airports
Cheapest • Avg $196 (round-trip)
Shortest trip • 6h 32m (one-way)
Insights
Insights
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Expert advice
Flight Deals

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

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

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

Mon, Nov 9 - Wed, Nov 11
Frontier Logo
1:28 pm - 10:59 amSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
23h 31m1 stop Las Vegas Harry Reid Intl
Frontier Logo
12:14 pm - 12:33 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
22h 19m1 stop Las Vegas Harry Reid Intl
$196Frontier
Sat, Oct 3 - Tue, Oct 6
Frontier Logo
8:10 pm - 3:08 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
20h 58m1 stop Denver Intl
Frontier Logo
4:27 pm - 11:59 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
29h 32m1 stop Denver Intl
$207Frontier
Sat, Oct 10 - Sat, Oct 17
American Airlines Logo
5:23 pm - 12:36 amSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
9h 13m1 stop Chicago O'Hare Intl
American Airlines Logo
3:14 pm - 12:19 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
7h 05m1 stop Chicago O'Hare Intl
$217American Airlines
Sat, Oct 17 - Wed, Oct 28
American Airlines Logo
7:29 am - 2:17 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
8h 48m1 stop Chicago O'Hare Intl
American Airlines Logo
1:37 pm - 11:46 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 09m1 stop Los Angeles
$217American Airlines
Sat, Nov 7 - Sun, Nov 15
Southwest Logo
5:50 am - 10:50 amSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
7h 00m1 stop Dallas Love Field
Southwest Logo
12:15 am - 8:50 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
6h 35m1 stop Chicago Midway
$217Southwest
Tue, Oct 27 - Wed, Nov 11
Southwest Logo
4:55 pm - 11:55 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
9h 00m1 stop Phoenix Sky Harbor Intl
Southwest Logo
11:20 am - 10:00 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 40m1 stop Chicago Midway
$217Southwest
Wed, Dec 9 - Tue, Dec 15
Delta Logo
7:08 am - 2:44 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
9h 36m1 stop Salt Lake City
Delta Logo
6:00 am - 4:30 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
8h 30m1 stop Minneapolis St Paul
$217Delta
Sat, Dec 12 - Tue, Dec 15
Delta Logo
5:00 pm - 10:53 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
7h 53m1 stop Salt Lake City
Delta Logo
1:30 pm - 9:28 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
5h 58m1 stop Salt Lake City
$217Delta
Wed, Mar 3 - Mon, Mar 8
United Airlines Logo
7:04 pm - 12:14 amSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
7h 10m1 stop Chicago O'Hare Intl
United Airlines Logo
10:40 pm - 8:19 amSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
7h 39m1 stop Chicago O'Hare Intl
$227United Airlines
Sat, Jan 30 - Mon, Feb 1
United Airlines Logo
9:13 am - 4:09 pmSTL  Lambert-St Louis-SEA Seattle/Tacoma Intl
8h 56m2 stops Denver Intl San Francisco
United Airlines Logo
2:30 pm - 11:24 pmSEA  Seattle/Tacoma Intl-STL Lambert-St Louis
6h 54m1 stop Chicago O'Hare Intl
$232United Airlines
Booking Insights

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

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

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

Round-trip flights from St. Louis to Seattle start at $196. Prices are below average for this route right now, with typical round-trip fares ranging from $289 to $517. The lowest price found in the past 5 days was $196 on Frontier.

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

Tuesday is the cheapest day of the week to fly from St. Louis to Seattle, it is 6% cheaper than the average day. Friday is the most expensive day with flight prices 6% higher than average. Based on deals found by KAYAK users in the last 12 months.

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

  • February is the cheapest month to fly from St. Louis to Seattle at $237 round-trip.
  • July ($505) and June ($456) are the most expensive months.
  • The price difference between flying in the cheapest and most expensive months is 113% on average.
This is based on KAYAK aggregated and averaged internal data over the past 12 months.

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

Flights from St. Louis to Seattle are cheapest 7 weeks before departure. Booking in this window typically costs about 42% 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 St. Louis to Seattle

 
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 St. Louis to Seattle flights

Low season

February

Cheapest flight

$104
Best time to beat the crowds with an average 41% drop in price.
Most popular time to fly with an average 27% increase in price.
Flight from St. Louis to Seattle

When to book flights from St. Louis to Seattle

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

Your St. Louis to Seattle flight questions, answered

Find helpful route details based on KAYAK data, including flight times, airports, airlines and booking questions.

  • How far is downtown Seattle from Seattle Tacoma International Airport?

    Downtown Seattle is about 15 miles away from the airport. There are multiple ways to get there, although they all vary in cost, speed, and convenience. For instance, the fastest way to downtown Seattle would be by taking a taxi. They can easily be found on the third floor of the parking garage and take less than 25min. Alternatively, you can opt for public transport, which is significantly cheaper but slower than a taxi. To board your train, just head to the bridge on the fourth floor of the parking garage where the terminal is located.

  • Does Seattle Tacoma Airport offer wheelchair services?

    Seattle Airport offers complimentary wheelchair services to aid travelers in getting from the plane to baggage claim to the ground transportation center with ease. However, due to logistics reasons, the airport mainly works with the airlines to provide these services. Therefore, the best way to get wheelchair assistance would be by booking with your airline, which will then put on a note on your reservation record informing the airport that you require special assistance.

  • Is on-site parking available at St. Louis Lambert International Airport?

    St. Louis Lambert Airport has plenty of on-site parking options. Two are specially dedicated for long-term parking. They include Long-Term Parking Lot B and Long-Term Parking Lot C, which is split into a covered and uncovered section. Long-Term Parking Lot B is located past Daily Parking Lot A east of the terminal, while Parking Lot C is situated southwest of the airport.

  • Which airline has a lounge in St Louis Lambert Airport?

    St. Louis Lambert Airport has about four lounges for guests to hang out and relax while waiting for their boarding call. The American Airlines Admirals Club is located Airside on Terminal 1 near Gate C1. The Wingtips Lounge, which is open to all travelers regardless of the airline, is located in Terminal 2 near Gate E22. Here you can find a range of snacks and beverages as well as a TV, charging stations, and Wi-Fi in case you need to send a few emails before boarding your flight.

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

    Among airlines operating St. Louis to Seattle 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.

  • What airlines are available from St. Louis to Seattle?

    2 airlines operate flights between St. Louis and Seattle. The airlines offering nonstop flights on this route include:

    • Alaska Airlines
    • Southwest

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

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

  • Which airlines include bags at no extra cost on St. Louis to Seattle 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
    • Southwest: a cabin bag and a checked bag in Economy Class
    • American Airlines: a cabin bag and a checked bag in First Class

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

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

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

    • Economy Class
    • Business Class
    • First Class

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

    On this route, layover flights are cheaper than nonstop options on average. Layover fares average $196 round-trip via Dallas/Fort Worth (DFW), compared to $415 for nonstop.

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

    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 St. Louis to Seattle?

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

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

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

    • Denver Intl (DEN) - 35% of one-stop connections
    • Chicago O'Hare Intl (ORD) - 23% of one-stop connections
    • Salt Lake City (SLC) - 18% of one-stop connections
    • Las Vegas Harry Reid Intl (LAS) - 6% of one-stop connections

    Denver Intl (DEN) handles the largest share of one-stop connections on this route.

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

    Yes. Being flexible with your travel dates can save you up to 12% on the St. Louis to Seattle route. Tuesday is the cheapest departure day at $375 round-trip on average, while Friday is the most expensive at $422, a difference of $47. KAYAK's flexible dates feature shows options up to 3 days before and after your selected dates, making it easier to compare nearby fares.

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

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

  • What popular places can I visit in Seattle?

    Some of the most popular sights in Seattle are Pike Place Market, Lumen Field and Space Needle. These are among the most viewed places in Seattle on KAYAK.

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

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

    • Earliest: departs at 6:00 am and lands at 10:30 am
    • Latest: departs at 7:36 pm and lands at 12:06 am.

    The flight takes about 4h 30m.

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

    Last-minute fares on this route - booked within 2 weeks of departure - run 45% above the route average of $398. Book 7 weeks before departure for the lowest fares.

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

    A nonstop flight from St. Louis to Seattle takes 4h 30m, covering 1,704 miles.

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

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

    One-way fares from St. Louis to Seattle are currently lower than usual. Average one-way flight prices are about $111, which is 55% below the typical average for this route.

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

    Flying via Dallas Love Field (DAL) gives the shortest average 1-stop total travel time at 6h 32m, compared with 6h 34m via Salt Lake City (SLC) and 6h 50m via Chicago Midway (MDW).

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

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

  • What car rental options are available at Seattle/Tacoma Intl Airport (SEA)?

    Seattle/Tacoma Intl Airport (SEA) hosts 5 major car rental companies, with daily rates starting from around $4 for economy cars. Top options include:
    • Fox
    • Europcar
    • Thrifty
    • Budget
    • Dollar

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

    Round-trip flights from St. Louis to Seattle range from $289 to $517, with an average of $398 over the past 12 months. Anything below $289 counts as a good deal.

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

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

Your guide to booking St. Louis to Seattle flights

Get tips on when to book, when to fly and what to know before your trip.
  • If your dates can be flexible, aim for a Tuesday departure instead of Friday. On this route, Tuesday flights average $375 - about $47 less than Friday (11% savings) based on the last 12 months.
  • For the best chance at a low fare, aim to book around 7 weeks before you fly. On this route, that window historically saves about 42% versus last-minute pricing (KAYAK booking data, last 12 months).
  • If you can choose when to travel, plan your St. Louis to Seattle trip for February. Fares historically average $237 round-trip in that month - typically $268 less than the most expensive month, which is July (based on the last 12 months).
  • If you have the time, taking a 1-stop flight through Dallas/Fort Worth Airport (DFW) can be cheaper than flying direct. The cheapest layover option averages $196 round-trip on this route - about $219 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 Seattle/Tacoma Intl Airport.
    - Seattle Airport Marriott
    - Coast Gateway Hotel
    - Fairfield by Marriott Inn & Suites Seattle Sea-Tac Airport
  • If you’re looking for a way to cut down on the cost of tickets, consider booking connecting flights instead of a direct one. More often than not, airlines will charge lower prices for connecting flights on the same route.
  • While booking your flight, pay close attention to the in-flight services provided. This is because different flights will have varying services available even when they are facilitated by the same airline.
  • If you’re traveling with the kids, you’ll be happy to learn that Seattle Tacoma International Airport (SEA) has a child play area where the kids can play around as you clear with baggage claim. It is located on Concourse D next to Qdoba.
  • St Louis Lambert International Airport (STL) is a pet-friendly airport. If you’re traveling with a service animal or pet, there are multiple relief areas for the four-legged friends. You’ll find two on Concourse E close to Gate E4 while the other one is found on Concourse C near Gate C24.
  • If you need a private space to nurse your child at Seattle Airport, you should check out the nursing pods on Concourse A, near Gate A10E.

Prefer to fly direct from St. Louis to Seattle?

 
Find which airlines fly direct from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport, which days they fly and book direct flights.

Direct departures

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

Direct returns

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

More options for your flight from St. Louis to Seattle

Complete your trip to Seattle with a hotel stay or car rental