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

View $129 flight on Sun, Aug 31, 2025Opens in a new window

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

Prices were available within the past 7 days and start at $129 for one-way flights and $243 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Sun, Aug 31 - Sun, Sep 7
SEA
Seattle
STL
St. Louis
$243 Roundtrip, found 1 hour ago
$243
Roundtrip
found 1 hour ago
Select Delta flight, departing Sun, Aug 31 from Seattle to St. Louis, returning Sun, Sep 7, priced at $243 found 1 hour ago
Flights from Seattle (SEA) to St. Louis (STL)
Origin airport
Seattle - Tacoma Intl.
Destination airport
Lambert-St. Louis 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
6 hours 42 mins

Frequently asked questions

How much is a Delta Air Lines flight from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
You can find cheap round-trip Delta Air Lines flights from $243 from SEA to STL by filtering your results from "Price (lowest to highest)" on Expedia. Or search for bargains 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 SEA to STL with Delta Air Lines?
January is one of the most affordable months to jet off to St. Louis with Delta Air Lines. You could also find great prices on return and one-way tickets in February.
What is the cheapest time to book flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL) with Delta Air Lines?
Start searching one to three months ahead of your departure date to get cheaper fares on Delta Air Lines flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also reduce costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Nail your timing, and you can enjoy significant savings on domestic flights.*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 Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
To find out if there's a direct trip from SEA to STL with Delta Air Lines or any other airlines, select the "Nonstop" filter when browsing for tickets.
What is the earliest Delta Air Lines flight from SEA to STL?
Browse Delta Air Lines's earliest flights from SEA to STL by using the "Morning" and "Early Morning" filters. Not only will you get to where you're going 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 St. Louis?
Get on a Delta Air Lines flight from Seattle - Tacoma Intl. Airport (SEA) to St. Louis, and you'll probably land at Lambert-St. Louis Intl. Airport (STL). This is the airline's main hub in this city.
Why fly with Delta Air Lines from SEA to STL?
Flying from SEA to STL with Delta Air Lines means enjoying a range of perks, such as an excellent in-flight experience and a rewarding loyalty program. Plus, when you book through Expedia, One Key™ members can collect OneKeyCash™* to spend on select future travel purchases. That's on top of the Delta SkyMiles points you can earn with Delta Air Lines.*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 Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
Typically, you can modify or cancel your flight, although there may be a charge if you made your booking over 24 hours ago. Need to keep your options open? Make use of our "No cancel fee" and "Changes included" filters to find flights that won't charge you extra if you need to adjust your plans. To update your itinerary, head to "Trips," select your flight and click on "Manage Booking" for more details.

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*Available to One Key members.