Cheap flights from St. Louis to Seattle from $69
This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Seattle departing on 9/18. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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United Airlines flights from St. Louis to Seattle
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How to get the cheapest flight ticket from St. Louis to Seattle
Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip
What is the typical price of a round-trip flight between St. Louis and Seattle?
What is the cheapest month to fly to Seattle?
In general, September is the cheapest month to fly from St. Louis to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $289. If you don’t want to visit Seattle in September, then you should wait until October to fly from St. Louis, when ticket prices are also cheap, with an average price of $296.
What is the cheapest day to depart on your flight to Seattle?
On average, the least expensive day to fly to Seattle from St. Louis is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as $463. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from St. Louis because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $559.
What is the cheapest time of day to depart on your flight to Seattle?
Flying to Seattle from St. Louis in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $455 when looking at flights departing in the afternoon. Flights to Seattle are more costly in the morning, with an average ticket price of $506. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.
What is the cheapest Lambert-St Louis to Seattle/Tacoma Intl flight route?
Fly from Lambert-St Louis to Seattle/Tacoma Intl for the best Lambert-St Louis - Seattle/Tacoma Intl flight prices
How far in advance should I book a flight to Seattle?
You are more likely to see cheaper flights to Seattle from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $359 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from St. Louis for as low as $288 on momondo.
What cabin class options are available on Lambert-St Louis to Seattle/Tacoma Intl flights?
There are 4 cabin classes available to choose from on Lambert-St Louis to Seattle/Tacoma Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.
Can stopping save me money on St. Louis to Seattle flights?
No. A direct flight is the cheapest option for a flight between St. Louis to Seattle.
How have St. Louis to Seattle flight prices changed over time?
As of July 2025, prices for St. Louis to Seattle flights are approximately 30% cheaper when compared to flights at the same time last year.
What is the cheapest airline that flies from Lambert-St Louis to Seattle/Tacoma Intl?
Frontier, United Airlines, and American Airlines are the most popular carriers operating from Lambert-St Louis to Seattle/Tacoma Intl
What airlines fly to Seattle?
Alaska Airlines, American Airlines and Delta are the top three most popular airlines that fly to Seattle from St. Louis according to our data. Alaska Airlines is the first choice among our users, with 69% of people opting to fly with this airline when traveling to Seattle. Keep in mind that there are 7 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.
How many flights depart from St. Louis to Seattle on average per day?
As of July 2025, 11 flights take off from St. Louis and land in Seattle each day. The most common flight departure time for this route is 6:00AM, with 45% of daily flights taking off at noon.
How many flights depart from St. Louis to Seattle on average per week?
The number of flights available between St. Louis and Seattle is 79 per week as of July 2025. The most frequent departure day is Thu, with 20% of weekly flights leaving on this day.
When to book flights from St. Louis to Seattle
Cheap St. Louis to Seattle (STL to SEA) flight deals and tips
Find info about flight duration, direct flights, and airports for your flight from St. Louis to Seattle
How far is Lambert-St Louis to Seattle/Tacoma Intl by plane?
Lambert-St Louis and Seattle/Tacoma Intl are 1719.6 mi apart from one another. By plane, this route typically takes 4h 24m.
When did momondo last update prices for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?
Prices for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport are updated daily.
How many operators does momondo search for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?
As of July 2025, there are 7 operators available to choose from for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport.
How old do you have to be to fly from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport.
What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?
The required travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Seattle/Tacoma Intl Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.
What is the most popular plane model from St. Louis to Seattle?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from St. Louis to Seattle is Boeing 737 (35.71% of total bookings). The next most popular plane models are Boeing 737 MAX 9 (29.51%), Boeing 737-900 Passenger/BBJ3 (winglets) (16.04%), and Boeing 737-800 Passenger/BBJ2 (winglets) (8.66%).
What is the most popular airline from St. Louis to Seattle?
Based on momondo bookings for this flight route, the most popular airline on flight routes from St. Louis to Seattle is Alaska Airlines (62% of total bookings). The next most popular airlines are American Airlines (10%), Delta (9%), and Hawaiian Airlines (7%).
Best airlines flying from St. Louis to Seattle
Compare and see reviews for airlines that fly from St. Louis to Seattle with momondo
| Airline | Rating | Free Cancellation | Price | ||
|---|---|---|---|---|---|
| PriceFrom $94 | Free Cancellation | Rating 8.0 7,983 reviews | |||
| PriceFrom $110 | Free Cancellation | Rating 5.9 3,284 reviews | |||
| PriceFrom $179 | Free Cancellation | Rating 8.0 4,270 reviews | |||
| PriceFrom $196 | Free Cancellation | Rating 7.2 10,000 reviews | |||
| PriceFrom $216 | Free Cancellation | Rating 7.4 8,861 reviews | |||
| PriceFrom $236 | Free Cancellation | Rating 8.0 10,000 reviews | |||
| PriceFrom $238 | Free Cancellation | Rating 7.8 2,545 reviews |
Southwest Flights From St. Louis to Seattle
Southwest operates around 4 flights from St. Louis to Seattle every week. The average price of these flights found in the last 72 hours has been $387, but momondo users have found Southwest deals from St. Louis to Seattle from as low as $179 round-trip. Southwest has been scored 8.0/10 in 4,270 reviews.
Alaska Airlines Flights From St. Louis to Seattle
Another popular option for St. Louis to Seattle flights is Alaska Airlines (8.0/10, 10,000 ratings). Alaska Airlines flies from St. Louis to Seattle around 6 times per week, with deals starting from $236 round-trip and rising to an average price of around $390.
Traveling to a place near Seattle?
Book flights to Seattle if you plan to visit one of these locationsWhy use momondo?
Why should I use momondo to find a flight deal from St. Louis to Seattle?
momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to Seattle. Millions of users trust and use momondo every year so you are in good hands.
Can I find flights from St. Louis to Seattle with flexible booking policies on momondo?
Yes. momondo allows you to filter the results for St. Louis to Seattle flights to just show those with flexible booking policies.
How can momondo help me find flights from St. Louis to Seattle?
Once all potential St. Louis to Seattle flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.
I’m not ready to book a flight from St. Louis to Seattle right now. Can momondo alert me if prices change?
Of course. momondo tracks the price of St. Louis to Seattle flights. All you need is a valid email address and we will do the rest; it is that quick and easy.