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$156+ Cheap flights from St. Louis (STL) to Ottawa (YOW)

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 12/5. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
Oct 31 — Nov 71
Fri 10/31
Fri 11/7
1 adult, Economy
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Cheap flight deals from St. Louis to Ottawa

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Ottawa (YOW). 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 1, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$361
(Air Canada)

One-way from

$156
(Air Canada)

Popular in

July

Cheapest in

February

Average price

$816
Provider with most accurate pricing for Lambert-St Louis-Ottawa flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Ottawa flights.
Search Deals
From Lambert-St Louis to Ottawa
Search Deals
One-way flight from Lambert-St Louis to Ottawa
Search Deals
Highest demand for flights based on searches. 19% potential increase in price ($174 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease ($31 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 St. Louis to Ottawa

Cheapest flights from St. Louis to Ottawa
Explore the most affordable flight options available from St. Louis to Ottawa. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 1, 2025.

This Air Canada deal was found by Cheapflights users on 9/29. 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.
Fri 12/54:05 pmSTL - YOW
1 stop6h 03mAir Canada
Wed 12/1010:20 amYOW - STL
1 stop6h 09mAir Canada
Deal found 9/29$361
This American Airlines deal was found by Cheapflights users on 9/29. 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.
Fri 12/51:59 pmSTL - YOW
2 stops9h 42mAmerican Airlines
Wed 12/1010:00 amYOW - STL
2 stops25h 25mAmerican Airlines
Deal found 9/29$386
This United deal was found by Cheapflights users on 9/29. 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.
Fri 12/56:42 pmSTL - YOW
2 stops17h 36mMultiple Airlines
Wed 12/109:15 amYOW - STL
1 stop7h 14mMultiple Airlines
Deal found 9/29$446

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to Ottawa 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 1, 2025.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

St. Louis

Fly to

Ottawa

Route

Depart

Return

Price

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

4:05 pm-11:08 pm

1 stop6h 03m

Ottawa

Wed 12/10

10:20 am-3:29 pm

1 stop6h 09m

$361

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

1:59 pm-12:41 am

2 stops9h 42m

Ottawa

Wed 12/10

10:00 am-10:25 am

2 stops25h 25m

$386

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

6:42 pm-1:18 pm

2 stops17h 36m

Ottawa

Wed 12/10

9:15 am-3:29 pm

1 stop7h 14m

$446

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

4:05 pm-11:08 pm

1 stop6h 03m

$156

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

6:42 pm-1:36 pm

2 stops17h 54m

$165

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 12/5

6:26 pm-12:42 am

3 stops29h 16m

$178

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 10/14

9:20 am-5:06 pm

1 stop6h 46m

$223

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 10/9

10:57 am-5:20 pm

1 stop29h 23m

$273

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 10/6

4:00 pm-5:20 pm

2 stops24h 20m

$287

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 10/12

1:30 pm-8:14 pm

1 stop5h 44m

$322

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/29

Showing 1-10 of 11 results
1
2

Compare providers for flights from St. Louis to Ottawa

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 St. Louis to Ottawa 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 St. Louis-Ottawa flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Ottawa flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Ottawa flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Ottawa 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 St. Louis-Ottawa 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 St. Louis to Ottawa

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

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

Currently, January is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $294). Flying from St. Louis to Ottawa in September is currently the most expensive (average of $428). 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 St. Louis to Ottawa?

Reviews of airlines servicing Ottawa

Get insights into the airlines that provide service to Ottawa. 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 Ottawa. Reviews last updated October 1, 2025.
Get a feel of what it's like to fly with United Airlines and Air Canada from St. Louis to Ottawa by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
8,929 reviews

Entertainment

7.1

Boarding

7.7

Food

6.6

Comfort

7.3

Crew

8.1

Overall

7.4

Reviews

1 / 20
4.0
Okay

Tim,Sep 2025

IAD - GSP

This was pretty bad. It’s chaos at the Dulles boarding gates for the small regional jets because they use one gate to board 3-4 flights at a time. So, it’s difficult knowing where and when to go. There is little space for any size of carrry-on, so most had to gate check their bags. However, the worst of it was that our single flight attendant fell asleep before we took off and the pilot couldn’t do so until she responded to his messages. My wife had to wake her up! So we were a little late leaving. Not to be thwarted, the flight attendant fell asleep right after take off and there was no sight of her during the flight. When the aircraft touched down, a tray of unsecured canned drinks came crashing onto the aisle up front. I can only assume someone didn’t do what they were supposed to. The pilot was great, but I’m sure he must not be happy with this crew member.
United Airlines
7.4
Good
8,929 reviews
United Airlines
7.4
Good
8,929 reviews

Entertainment

7.1

Boarding

7.7

Food

6.6

Comfort

7.3

Crew

8.1

Overall

7.4

Reviews

1 / 20
4.0
Okay

Tim,Sep 2025

IAD - GSP

This was pretty bad. It’s chaos at the Dulles boarding gates for the small regional jets because they use one gate to board 3-4 flights at a time. So, it’s difficult knowing where and when to go. There is little space for any size of carrry-on, so most had to gate check their bags. However, the worst of it was that our single flight attendant fell asleep before we took off and the pilot couldn’t do so until she responded to his messages. My wife had to wake her up! So we were a little late leaving. Not to be thwarted, the flight attendant fell asleep right after take off and there was no sight of her during the flight. When the aircraft touched down, a tray of unsecured canned drinks came crashing onto the aisle up front. I can only assume someone didn’t do what they were supposed to. The pilot was great, but I’m sure he must not be happy with this crew member.
Air Canada
7.1
Good
10,223 reviews
United Airlines
7.4
Good
8,929 reviews

Entertainment

7.1

Boarding

7.7

Food

6.6

Comfort

7.3

Crew

8.1

Overall

7.4

Reviews

1 / 20
4.0
Okay

Tim,Sep 2025

IAD - GSP

This was pretty bad. It’s chaos at the Dulles boarding gates for the small regional jets because they use one gate to board 3-4 flights at a time. So, it’s difficult knowing where and when to go. There is little space for any size of carrry-on, so most had to gate check their bags. However, the worst of it was that our single flight attendant fell asleep before we took off and the pilot couldn’t do so until she responded to his messages. My wife had to wake her up! So we were a little late leaving. Not to be thwarted, the flight attendant fell asleep right after take off and there was no sight of her during the flight. When the aircraft touched down, a tray of unsecured canned drinks came crashing onto the aisle up front. I can only assume someone didn’t do what they were supposed to. The pilot was great, but I’m sure he must not be happy with this crew member.

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Ottawa. 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 St. Louis to Ottawa?

    A quick flight from St. Louis to Ottawa can take about 6h 03m. Air Canada provides one of the quickest options available for as low as $361. St. Louis and Ottawa are separated by a distance of 878 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from St. Louis to Ottawa round-trip?

    Currently priced at $330, Air Canada will fly you from St. Louis to Ottawa and back. In addition to Air Canada, many other airlines offer competitively priced options for your trip. Check Cheapflights for deals on United Airlines for as low as $434. Air Canada is 55% cheaper than the average price of flights available within the next 90 days to this destination.

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

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

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

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

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

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

    Currently, January is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $294). Flying from St. Louis to Ottawa in September is currently the most expensive (average of $428). 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 Ottawa?

Book flights to Ottawa if you plan to visit one of these locations
Gatineau
Petawawa

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Top 2 airlines flying from St. Louis to Ottawa

Discover the top 2 airlines that operate flights from St. Louis to Ottawa. 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 1, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$330Average$834FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$434Average$824FlexibilityNo cancel feeOn-time69%

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