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St. Louis

$301+ Cheap flights from Ottawa (YOW) to St. Louis (STL)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/24. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
Nov 6 — Nov 131
Thu 11/6
Thu 11/13
1 adult, Economy
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Cheap flight deals from Ottawa to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Ottawa (YOW) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated October 7, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$301
(United Airlines)

Popular in

December

Cheapest in

September

Average price

$554
Provider with most accurate pricing for Ottawa-Lambert-St Louis flight deals.
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Provider most trusted by Cheapflights users for Ottawa-Lambert-St Louis flights.
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From Ottawa to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 4% potential increase in price ($31 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($10 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find flight deals from Ottawa to St. Louis

Cheapest flights from Ottawa to St. Louis
Explore the most affordable flight options available from Ottawa to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 7, 2025.

This United Airlines deal was found by Cheapflights users on 10/5. 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.
Wed 12/245:59 pmYOW - STL
1 stop6h 58mUnited Airlines
Tue 1/66:30 amSTL - YOW
1 stop9h 42mUnited Airlines
Deal found 10/5$301
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Wed 12/246:15 amYOW - STL
1 stop7h 12mUnited Airlines
Sat 1/37:00 amSTL - YOW
1 stop5h 32mUnited Airlines
Deal found 10/5$302
This United deal was found by Cheapflights users on 10/5. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/243:10 pmYOW - STL
1 stop9h 47mMultiple Airlines
Mon 1/54:05 pmSTL - YOW
1 stop6h 03mMultiple Airlines
Deal found 10/5$308
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Wed 12/245:59 pmYOW - STL
1 stop6h 58mUnited Airlines
Sun 1/46:35 pmSTL - YOW
2 stops18h 55mUnited Airlines
Deal found 10/5$354
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Wed 12/245:00 amYOW - STL
2 stops13h 54mUnited Airlines
Mon 1/59:55 amSTL - YOW
2 stops10h 23mUnited Airlines
Deal found 10/5$403
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Tue 12/237:27 pmYOW - STL
2 stops18h 00mUnited Airlines
Sat 1/37:00 amSTL - YOW
1 stop5h 32mUnited Airlines
Deal found 10/5$422
This United deal was found by Cheapflights users on 10/5. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/246:15 amYOW - STL
1 stop7h 12mMultiple Airlines
Sun 1/44:05 pmSTL - YOW
1 stop8h 33mMultiple Airlines
Deal found 10/5$464
This Air Canada deal was found by Cheapflights users on 10/5. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/121:55 pmYOW - STL
1 stop6h 43mAir Canada
Sun 10/199:15 amSTL - YOW
1 stop4h 49mAir Canada
Deal found 10/5$555

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ottawa to St. Louis 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 October 7, 2025.
Use the filters below to find and compare flights from Ottawa to St. Louis that are best for you.

Fly from

Ottawa

Fly to

St. Louis

Route

Depart

Return

Price

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 3/24

10:35 am-2:18 pm

1 stop4h 43m

Lambert-St Louis

Tue 3/31

6:45 am-9:14 pm

1 stop13h 29m

$301

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/24

5:59 pm-11:57 pm

1 stop6h 58m

Lambert-St Louis

Tue 1/6

6:30 am-5:12 pm

1 stop9h 42m

$301

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 2/24

5:14 pm-9:00 pm

1 stop4h 46m

Lambert-St Louis

Tue 3/3

7:00 am-1:34 pm

1 stop5h 34m

$302

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/24

3:10 pm-11:57 pm

1 stop9h 47m

Lambert-St Louis

Mon 1/5

4:05 pm-11:08 pm

1 stop6h 03m

$308

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/24

6:15 am-12:27 pm

1 stop7h 12m

Lambert-St Louis

Sun 1/4

6:35 pm-2:30 pm

2 stops18h 55m

$354

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/24

6:15 am-12:27 pm

1 stop7h 12m

Lambert-St Louis

Mon 1/5

6:35 pm-2:30 pm

2 stops18h 55m

$354

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/24

6:00 am-2:26 pm

2 stops9h 26m

Lambert-St Louis

Sat 1/3

7:00 am-1:32 pm

1 stop5h 32m

$361

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/6

Compare providers for flights from Ottawa to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ottawa to St. Louis in October.
ProviderPrice AccuracyTrust Score*
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice 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 Ottawa-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ottawa-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ottawa-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ottawa-St. Louis 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 Ottawa-St. Louis 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 Ottawa to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Ottawa 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 Ottawa to St. Louis

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

Currently, March is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $392). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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.

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

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. 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. Louis. Reviews last updated October 7, 2025.
Read through reviews of airlines operating flights from Ottawa to St. Louis, such as Air Canada. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Air Canada
7.1
Good
10,245 reviews

Overall

7.1

Boarding

7.3

Food

6.3

Comfort

7.1

Entertainment

6.8

Crew

7.8

Reviews

1 / 20
10.0
Excellent

janet,Sep 2025

YOW - YYZ

Really appreciated the leg room despite purchasing an economy ticket. Appreciated the extra complimentary wine. Nice touch. Was given immediate support without asking at check in, at the machine!! Ottawa's boarding was very organized with distinct rows in waiting room. Allowed for the main hall to not be blocked by people waiting to board.
Air Canada
7.1
Good
10,245 reviews
Air Canada
7.1
Good
10,245 reviews

Overall

7.1

Boarding

7.3

Food

6.3

Comfort

7.1

Entertainment

6.8

Crew

7.8

Reviews

1 / 20
10.0
Excellent

janet,Sep 2025

YOW - YYZ

Really appreciated the leg room despite purchasing an economy ticket. Appreciated the extra complimentary wine. Nice touch. Was given immediate support without asking at check in, at the machine!! Ottawa's boarding was very organized with distinct rows in waiting room. Allowed for the main hall to not be blocked by people waiting to board.

Related info for your journey

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

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

    Departing from Ottawa to St. Louis will take you 4h 43m. The distance from Ottawa to St. Louis is about 878 mi.

  • What is the cheapest airline to fly from Ottawa to St. Louis round-trip?

    Our cheapest airline available from Ottawa to St. Louis is Air Canada. Our recent data shows that you can find tickets from as low as $511 on this airline. You may be able to fly from Ottawa to St. Louis for 18% less than the average price by searching for this airline.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ottawa to St. Louis 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 Ottawa to St. Louis?

    Currently, March is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $392). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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 St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

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Top airline flying from Ottawa to St. Louis

Discover the top airline that operate flights from Ottawa to St. Louis. 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 October 7, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$511Average$677FlexibilityNo cancel feeOn-time67%

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