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St. Louis

$172+ Cheap flights from Ottawa (YOW) to St. Louis (STL)

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 4/12. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
Mar 30 — Apr 61
Mon 3/30
Mon 4/6
1 adult, Economy
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Cheap 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 February 28, 2026.

This United Airlines deal was found by Cheapflights users on 2/26. 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 3/37:30 pm
YOW
-
STL
1 stop15h 43m
United Airlines
Thu 3/56:25 am
STL
-
YOW
2 stops7h 05m
United Airlines
Deal found 2/26$618
This Air Canada deal was found by Cheapflights users on 2/24. 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 3/19:15 am
YOW
-
STL
1 stop7h 14m
Air Canada
Tue 3/36:25 am
STL
-
YOW
1 stop9h 42m
Air Canada
Deal found 2/24$619
This Air Canada deal was found by Cheapflights users on 2/26. 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.
Tue 3/311:10 am
YOW
-
STL
1 stop10h 55m
Air Canada
Thu 3/57:41 am
STL
-
YOW
1 stop12h 37m
Air Canada
Deal found 2/26$653
This United Airlines deal was found by Cheapflights users on 2/25. 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.
Sun 3/15:11 pm
YOW
-
STL
1 stop4h 54m
United Airlines
Tue 3/36:25 am
STL
-
YOW
1 stop13h 53m
United Airlines
Deal found 2/25$715

Find 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 February 28, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Popular in

April

Cheapest in

January
Provider with most accurate pricing for Ottawa-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ottawa-Lambert-St Louis flights.
Search Deals
Highest demand for flights based on searches. 15% potential increase in price ($107 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($25 potential savings vs. average RT price).
Search Deals

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 February 28, 2026.
Use the filters below to find and compare flights from Ottawa to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sun 4/12

10:44 am-9:08 pm

1 stop11h 24m

$172

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 4/8

10:44 am-9:13 pm

1 stop11h 29m

$173

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 4/13

7:30 pm-8:25 am

2 stops13h 55m

$178

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 4/13

7:00 am-11:19 pm

3 stops41h 19m

$235

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sun 4/12

3:55 pm-11:25 pm

3 stops32h 30m

$247

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/25

Sorted by cheapest first
  • 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, May is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $276). 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.

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 February 28, 2026.
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
10,757 reviews

Boarding

7.3

Overall

7.1

Comfort

7.1

Crew

7.8

Entertainment

6.8

Food

6.3

Reviews

1 / 20
4.0
Okay

Sugith,Jan 2026

YSB - YYZ

Left 2 hours late. Stuck on plane for an hour after boarding before take off.
Air Canada
7.1
Good
10,757 reviews
Air Canada
7.1
Good
10,757 reviews

Boarding

7.3

Overall

7.1

Comfort

7.1

Crew

7.8

Entertainment

6.8

Food

6.3

Reviews

1 / 20
4.0
Okay

Sugith,Jan 2026

YSB - YYZ

Left 2 hours late. Stuck on plane for an hour after boarding before take off.

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.

  • 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 $343 on this airline. You may be able to fly from Ottawa to St. Louis for 41% 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, May is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $276). 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
Swansea
Fairview Heights
Fenton
Maryland Heights
Collinsville
Eureka
Wentzville
Glencoe
Chesterfield
Alton
Farmington
Festus

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Alternative routes for Ottawa to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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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 February 28, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$343Average$641FlexibilityNo cancel feeOn-time67%

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