Seattle

$114+ Cheap flights from St. Louis to Seattle (STL - SEA)

STL — SEA
Dec 4 — Dec 111
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1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

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Cheapflights Tip: The best prices from Lambert-St Louis to Seattle/Tacoma Intl are usually found in February or March, booked 46 days in advance, depart on a Friday or Saturday and return on a Tuesday

Cheap flight deals from St. Louis to Seattle

Cheapest flights from St. Louis to Seattle

Wed 12/25:20 pm -
1 stop8h 33m
Wed 12/911:15 pm -
1 stop8h 04m
Deal found 11/2$227
Sat 12/58:40 am -
2 stops9h 43m
Tue 12/82:05 pm -
1 stop6h 54m
Deal found 11/2$232
Wed 12/27:08 am -
1 stop9h 35m
Mon 12/79:50 am -
1 stop8h 42m
Deal found 11/2$237
Wed 12/22:25 pm -
1 stop11h 10m
Wed 12/95:40 am -
2 stops9h 45m
Deal found 11/2$238
Sat 12/58:40 am -
2 stops9h 43m
Mon 12/75:05 am -
1 stop5h 48m
Deal found 10/31$242
Mon 12/217:46 pm -
1 stop6h 24m
Mon 12/2811:59 pm -
1 stop8h 36m
Deal found 11/1$247
Fri 12/47:58 pm -
1 stop21h 45m
Fri 12/114:58 pm -
1 stop15h 59m
Deal found 11/4$253
Fri 12/46:32 am -
1 stop10h 31m
Mon 12/711:15 pm -
1 stop8h 04m
Deal found 11/3$257
Mon 12/217:46 pm -
1 stop6h 24m
Sun 12/2711:59 pm -
1 stop8h 36m
Deal found 11/4$267
Tue 12/225:16 pm -
1 stop8h 37m
Wed 12/3011:59 pm -
1 stop8h 36m
Deal found 10/31$273
Fri 11/203:04 pm -
2 stops23h 33m
Thu 11/264:37 pm -
1 stop16h 26m
Deal found 10/30$274

Find flight deals from St. Louis to Seattle

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$227
(Delta)

One-way from

$114
(Delta)

Popular in

July

Cheapest in

February

Average price

$400

Good round-trip deal

$439 or less

Good one-way deal

$208 or less
Provider with most accurate pricing for Lambert-St Louis-Seattle/Tacoma Intl flight deals.
Provider most trusted by Cheapflights users for Lambert-St Louis-Seattle/Tacoma Intl flights.
From Lambert-St Louis to Seattle/Tacoma Intl
One-way flight from Lambert-St Louis to Seattle/Tacoma Intl
Highest demand for flights based on searches. 21% potential increase in price ($106 potential increase over avg. RT price).
Cheapest flight prices on average. 3% potential price decrease ($14 potential savings vs. average RT price).
Average for round-trip flights in November 2026
Price to beat on a round-trip flight from Lambert-St Louis to Seattle/Tacoma Intl.
Price to beat on a one-way flight from Lambert-St Louis to Seattle/Tacoma Intl.

Cheapflights Fare Finder

 
Use the filters below to find and compare flights from St. Louis to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Wed 12/9

6:25 am-1:00 pm

1 stop8h 35m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$114
Quickest round-trip

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Tue 12/8

3:32 pm-8:49 pm

1 stop7h 17m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$114

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Tue 12/15

7:27 am-3:58 pm

1 stop10h 31m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$114

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Wed 12/16

8:40 am-4:22 pm

2 stops9h 42m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$119

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Tue 12/15

11:20 am-7:05 pm

2 stops9h 45m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$119

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Wed 1/27

6:20 am-2:40 pm

1 stop10h 20m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$119

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Mon 1/18

6:10 am-12:27 pm

1 stop8h 17m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$124

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Mon 1/18

5:40 pm-12:55 am

2 stops9h 15m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$129

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Thu 12/10

6:25 am-8:55 pm

2 stops16h 30m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$135

St. LouisSeattle

STL Lambert-St Louis - SEA Seattle/Tacoma Intl

STLSEA

Lambert-St Louis

Fri 11/20

3:04 pm-3:22 pm

1 stop26h 18m

Seattle/Tacoma Intl

Wed 12/31

12:00 am-2:00 am

Nonstop0h 00m

$165

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/2

Showing 1-10 of 22 resultsSorted by cheapest first
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Compare providers for flights from St. Louis to Seattle

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Seattle in November.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy2 starsTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust Score*1 star
CheapTicketsDealPrice Accuracy1 starTrust Score*3 stars
CheapOairPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on St. Louis-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Seattle flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from St. Louis to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from St. Louis with our price prediction graph.
Estimated round-trip price

Cheapflights Insights

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

How far ahead should I book a flight from St. Louis to Seattle?

The best time to book flights from St. Louis to Seattle is 45 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from St. Louis to Seattle?

Currently, February is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $237). Flying from St. Louis to Seattle in July is currently the most expensive (average of $525). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from STL to SEA?

Unlike at noon, when flights are generally more expensive, you can save up to 15% on flights from St. Louis to Seattle by exploring options for tickets in the evening.

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

Travelers seeking maximum savings on their St. Louis to Seattle flight should consider departing on Thursday at noon when fares are most often at their lowest. Wednesday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

How much does it cost to fly round-trip from St. Louis to Seattle?

Airfare is below average for this route at the moment.

St. Louis to Seattle flights typically cost between $248 and $558 in December.
The cheapest round-trip price found within the last 5 days was $227 on Delta (Dec 2-Dec 9).

The best insider tips for St. Louis to Seattle flights

Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Seattle trip
Our travel experts
Taryn White

Taryn White

Expert on STL

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Reviews of airlines servicing Seattle

Read through reviews of airlines operating flights from St. Louis to Seattle, such as Southwest,Alaska Airlines, andDelta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Comfort

8.0

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Crew

8.6

Reviews

1 / 20
8.0
Excellent

Patricia,Oct 2026

DAL - TPA

I love flying southwest, Both flights were packed full full - so not room for all carry one and bags had to be checked but still good flights.

Related info for your journey

  • What airports do I use to fly from St. Louis to Seattle?

    Booking a flight from Lambert-St Louis (STL) to Seattle/Tacoma Intl (SEA) is your only option if you wish to fly from St. Louis to Seattle. On a typical day, there are 3 flights from Lambert-St Louis to Seattle/Tacoma Intl, all of which are around 4h 28m for a nonstop flight. You can also purchase a plane ticket from 6 airlines when you book a flight from Lambert-St Louis to Seattle.

  • How popular is this St. Louis to Seattle flight route?

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

    Airlines like Delta, Southwest, and United Airlines fly from St. Louis to Seattle in about 6h 24m. The time it takes to get you to your destination can typically vary by up to 4h 30m. There are 1704 mi between St. Louis and Seattle. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • What are the cheapest airlines flying from St. Louis to Seattle round-trip?

    Currently priced at $124, Delta will fly you from St. Louis to Seattle and back. In addition to Delta, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Frontier and American Airlines - these airlines can fly you to your destination from $134 and $191, respectively. You may be able to fly from St. Louis to Seattle for 67% less than the average price by searching for these airlines.

  • What are the cheapest airlines to fly from St. Louis to Seattle one-way?

    The cheapest airlines for a one-way flight from St. Louis to Seattle are Southwest ($89), Delta ($93), and Frontier ($95).

  • What are the most reliable airlines from St. Louis to Seattle?

    The top 3 most reliable airlines when flying from St. Louis to Seattle are Qatar Airways (100%), Japan Airlines (95%) and American Airlines (90%).

  • What are the cheapest flights from St. Louis to Seattle?

    Looking for the cheapest flight from St. Louis to Seattle? While on average our users pay $1,042, our data indicates the cheapest price to be $173. The most popular route (Lambert-St Louis - Seattle/Tacoma Intl), is priced around $227.

  • Can I find deals for flights from St. Louis to Seattle that include hotel bookings?

    Yes. In addition to deals on St. Louis to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from St. Louis to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Seattle.

  • Can I find deals for business class flights from St. Louis to Seattle?

    Yes. Cheapflights offers flight deals from St. Louis to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from St. Louis to Seattle?

    Currently, February is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $237). Flying from St. Louis to Seattle in July is currently the most expensive (average of $525). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Renton
Lacey
Tacoma
Leavenworth
Tukwila
Snoqualmie
Puyallup
Lynnwood
Centralia
Kent
Tumwater
Ocean Shores
Ellensburg
Issaquah
Olympia
Lakewood
Poulsbo
Marysville
Shoreline

Browse thousands of different options on Cheapflights for your next trip

Top 6 airlines flying from St. Louis to Seattle

AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$124Average$247FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$134Average$281FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$191Average$390FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$196Average$426FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$219Average$383FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$221Average$434FlexibilityNo cancel feeOn-time75%

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