$129 Cheap Delta flights St. Louis (STL) to Seattle (SEA)

View $129 flight on Fri, Oct 31, 2025Opens in a new window

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$129 Cheap Delta flights St. Louis (STL) to Seattle (SEA)

Prices were available within the past 7 days and start at $129 for one-way flights and $226 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Mon, Sep 29 - Wed, Oct 1
STL
St. Louis
SEA
Seattle
$226 Roundtrip, found 1 hour ago
$226
Roundtrip
found 1 hour ago
Select Delta flight, departing Mon, Sep 29 from St. Louis to Seattle, returning Wed, Oct 1, priced at $226 found 1 hour ago
Delta
Sun, Aug 31 - Wed, Sep 10
STL
St. Louis
SEA
Seattle
$243 Roundtrip, found 9 hours ago
$243
Roundtrip
found 9 hours ago
Select Delta flight, departing Sun, Aug 31 from St. Louis to Seattle, returning Wed, Sep 10, priced at $243 found 9 hours ago
Flights from St. Louis (STL) to Seattle (SEA)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Sun Country Airlines, United
Popular airline
Alaska Airlines
Distance
1705 mi
Average flight time
2 hours 23 mins

Frequently asked questions

How much is a Delta Air Lines flight from Lambert-St. Louis Intl. Airport (STL) to Seattle - Tacoma Intl. Airport (SEA)?
You'll discover affordable round-trip Delta Air Lines flights from $226 from STL to SEA by sorting your results from "Price (lowest to highest)" on Expedia. Or look for deals from $129 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from STL to SEA with Delta Air Lines?
Delta Air Lines flights to Seattle are usually cheaper in the low-season months of January and February. Whether you're after a return or one-way ticket, you could score a better deal then.
What is the cheapest time to book flights from Lambert-St. Louis Intl. Airport (STL) to Seattle - Tacoma Intl. Airport (SEA) with Delta Air Lines?
For cheap Delta Air Lines fares from Lambert-St. Louis Intl. Airport (STL) to Seattle - Tacoma Intl. Airport (SEA), start searching one to three months before your intended departure. Reserving domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also affect the cost. Sunday is generally the cheapest, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your journey on a Sunday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does Delta Air Lines fly nonstop from Lambert-St. Louis Intl. Airport (STL) to Seattle - Tacoma Intl. Airport (SEA)?
Fill in your dates, click search and check the "Nonstop" filter on Expedia to find any direct flights from STL to SEA with Delta Air Lines or other airlines.
What is the earliest Delta Air Lines flight from STL to SEA?
Browse Delta Air Lines's earliest flights from STL to SEA by using the "Early Morning" and "Morning" filters. Not only will you arrive at your destination sooner, early departures also experience 20% fewer cancellations.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does Delta Air Lines fly into in Seattle?
Seattle - Tacoma Intl. Airport (SEA) is the primary Seattle hub for Delta Air Lines flights from Lambert-St. Louis Intl. Airport (STL).
Why fly with Delta Air Lines from STL to SEA?
With a rewarding loyalty program and an excellent in-flight experience, Delta Air Lines is a favorite for many travelers flying from STL to SEA. What's more, if you're a Delta SkyMiles and One Key™ member booking with Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles, which can go toward future travel.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
Can I change or cancel my Delta Air Lines flight from Lambert-St. Louis Intl. Airport (STL) to Seattle - Tacoma Intl. Airport (SEA)?
Typically, you can cancel or reschedule your flight, although there may be additional fees if your booking was made more than 24 hours ago. Prefer to keep your options open? Use our "No cancel fee" and "Changes included" filters to find flights that won't penalize you if you need to alter your plans. To make modifications, head to "Trips," select your flight and click on "Manage Booking" for more information.

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*Available to One Key members.