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St. Charles

$95+ Cheap flights from Seattle (SEA) to St. Charles, MO

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 6/2. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — STL
Apr 9 — Apr 161
Wed 4/9
Wed 4/16
1 adult, Economy
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to St. Charles are usually found in September or April, booked 81 days in advance, depart on a Thursday or Friday and return on a Wednesday

Cheap flight deals from Seattle to St. Charles

Keep the following information in mind while searching for Seattle to St. Charles flight deals. Data was last updated April 4, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$233
(Southwest)

One-way from

$95
(Delta)

Popular in

December

Cheapest in

September

Average price

$336
Provider with most accurate pricing for Seattle/Tacoma Intl-Lambert-St Louis flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Lambert-St Louis flights.
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From Seattle/Tacoma Intl to St. Charles
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One-way flight from Seattle/Tacoma Intl to St. Charles
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Highest demand for flights based on searches. 7% potential increase in price ($32 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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Find flight deals from Seattle to St. Charles

Cheapest flights from Seattle to St. Charles
Explore the most affordable flight options available from Seattle to St. Charles. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 4, 2025.

This Southwest deal was found by Cheapflights users on 4/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/610:55 pmSEA - STL
1 stop8h 35mSouthwest
Sun 6/88:25 pmSTL - SEA
1 stop6h 30mSouthwest
Deal found 4/3$233
This Delta deal was found by Cheapflights users on 4/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/35:30 amSEA - STL
1 stop5h 58mDelta
Mon 5/57:15 pmSTL - SEA
1 stop6h 47mDelta
Deal found 4/3$234
This Alaska Airlines deal was found by Cheapflights users on 4/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/296:03 pmSEA - STL
Nonstop3h 56mAlaska Airlines
Tue 5/66:30 amSTL - SEA
Nonstop4h 24mAlaska Airlines
Deal found 4/3$237
This CheapOair deal was found by Cheapflights users on 4/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/112:21 pmSEA - STL
1 stop18h 48mFrontier
Mon 5/56:53 pmSTL - SEA
1 stop7h 51mFrontier
Deal found 4/4$240
This Hawaiian Airlines deal was found by Cheapflights users on 4/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/16:03 pmSEA - STL
Nonstop3h 56mHawaiian Airlines
Sun 5/46:30 amSTL - SEA
Nonstop4h 24mHawaiian Airlines
Deal found 4/2$249
This Expedia deal was found by Cheapflights users on 4/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/256:03 pmSEA - STL
Nonstop3h 56mMultiple Airlines
Mon 4/286:58 pmSTL - SEA
1 stop7h 46mMultiple Airlines
Deal found 4/4$250
This United Airlines deal was found by Cheapflights users on 4/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/17:00 amSEA - STL
1 stop6h 47mUnited Airlines
Thu 5/87:00 amSTL - SEA
1 stop8h 43mUnited Airlines
Deal found 4/2$251
This American Airlines deal was found by Cheapflights users on 4/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/21:10 amSEA - STL
1 stop6h 44mAmerican Airlines
Wed 6/48:09 amSTL - SEA
1 stop7h 50mAmerican Airlines
Deal found 4/4$264

Cheapflights Fare Finder

Customize your flight search to find flights from Seattle to St. Charles that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated April 4, 2025.
Use the filters below to find and compare flights from Seattle to St. Charles that are best for you.

Fly from

Seattle

Fly to

St. Charles

Route

Depart

Return

Price

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Fri 6/6

10:55 pm-9:30 am

1 stop8h 35m

Lambert-St Louis

Sun 6/8

8:25 pm-12:55 am

1 stop6h 30m

$233

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Sat 5/3

5:30 am-1:28 pm

1 stop5h 58m

Lambert-St Louis

Fri 5/9

6:05 pm-11:47 pm

1 stop7h 42m

$234

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Tue 4/29

6:03 pm-11:59 pm

Nonstop3h 56m

Lambert-St Louis

Tue 5/6

6:30 am-8:54 am

Nonstop4h 24m

$237

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 5/1

12:21 pm-9:09 am

1 stop18h 48m

Lambert-St Louis

Mon 5/5

6:53 pm-12:44 am

1 stop7h 51m

$240

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 5/1

6:03 pm-11:59 pm

Nonstop3h 56m

Lambert-St Louis

Sun 5/4

6:30 am-8:54 am

Nonstop4h 24m

$249

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Fri 4/25

6:03 pm-11:59 pm

Nonstop3h 56m

Lambert-St Louis

Mon 4/28

6:58 pm-12:44 am

1 stop7h 46m

$250

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 5/1

7:00 am-3:47 pm

1 stop6h 47m

Lambert-St Louis

Thu 5/8

7:00 am-1:43 pm

1 stop8h 43m

$251

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Mon 6/2

1:10 am-9:54 am

1 stop6h 44m

Lambert-St Louis

Wed 6/4

8:09 am-1:59 pm

1 stop7h 50m

$264

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Mon 4/21

2:30 pm-5:15 pm

3 stops24h 45m

Lambert-St Louis

Thu 4/24

6:10 pm-7:51 pm

2 stops27h 41m

$424

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Mon 6/2

11:50 pm-10:47 am

1 stop8h 57m

$95

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/4

Showing 1-10 of 19 results
1
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Best time to book a flight from Seattle to St. Charles

Have a flexible travel schedule? Discover the best time to fly to St. Charles from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

Use this chart to determine the optimal time to book a round-trip flight from Seattle to St. Charles. Price data was last updated on March 28, 2025.

The best time to book flights from Seattle to St. Charles is 81 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 Seattle to St. Charles?

Currently, August is the cheapest month in which you can book a flight from Seattle to St. Charles (average of $311). Flying from Seattle to St. Charles in March is currently the most expensive (average of $356). 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 SEA to CH5?

Find hourly flight availability from Seattle to St. Charles. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated April 4, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to St. Charles as you normally would.

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

Use this chart to determine the cheapest time to fly round-trip from Seattle to St. Charles. Price data was last updated on December 16, 2024.

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

Weekly flight availability from Seattle to St. Charles

Explore weekly flight availability from Seattle to St. Charles. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated April 4, 2025.

The most flights from SEA to CH5 are scheduled on a Friday (10 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (3 on average).

Rainfall in St. Charles by month

Plan your trip to St. Charles by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Charles ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Charles when rainfall is around 2.2 in.

Temperature in St. Charles by month

Plan your trip to St. Charles by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Charles, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

Reviews of airlines servicing St. Charles

Get insights into the airlines that provide service to St. Charles. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to St. Charles. Reviews last updated April 4, 2025.
Read through reviews of airlines operating flights from Seattle to St. Charles, such as Alaska Airlines, Southwest and Delta. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Alaska Airlines
8.0
Very good
9,836 reviews
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Southwest
8.0
Very good
4,276 reviews
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Delta
8.0
Very good
7,901 reviews
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Hawaiian Airlines
7.9
Good
2,347 reviews
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
United Airlines
7.4
Good
8,621 reviews
Alaska Airlines
8.0
Very good
9,836 reviews

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥

Related info for your journey

Find useful and relevant information for your journey from Seattle to St. Charles. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Seattle to St. Charles?

    If you book a flight to St. Charles from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There are 6 flights from Seattle/Tacoma Intl to St. Charles per day from 7 different airlines.

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

    This flight path from Seattle/Tacoma Intl to St. Charles was viewed by 5 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

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

    To fly one-way, consider booking your trip with Delta, which is currently one of the cheapest options available, starting at $95. Southwest flights start at $100 while deals on United Airlines start at $109 one-way.

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

    The top 3 most reliable airlines when flying from Seattle to St. Charles are American Airlines (93%), Alaska Airlines (93%) and Hawaiian Airlines (93%).

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

    On average you can expect to pay $353 for a flight from Seattle to St. Charles. The cheapest flight overall is $118 while the most popular route, (Seattle/Tacoma Intl - Lambert-St Louis) is currently priced at $189.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Seattle to St. Charles 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 Seattle to St. Charles?

    Currently, August is the cheapest month in which you can book a flight from Seattle to St. Charles (average of $311). Flying from Seattle to St. Charles in March is currently the most expensive (average of $356). 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.

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Alternative routes for Seattle to St. Charles

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Top 7 airlines flying from Seattle to St. Charles

Discover the top 7 airlines that operate flights from Seattle to St. Charles. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated April 4, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$141Average$246FlexibilityNo cancel feeOn-time62%
DeltaCheapest$188Average$299FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$196Average$561FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$216Average$352FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$236Average$420FlexibilityNo cancel feeOn-time75%
Hawaiian AirlinesCheapest$237Average$393FlexibilityNo cancel feeOn-time85%
SouthwestCheapest$276Average$529FlexibilityNo cancel feeOn-time63%

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