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$173+ 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 9/15. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
ago. 19 — ago. 261
mar. 8/19
mar. 8/26
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 agosto 14, 2025.

Round-trip from

$736
(United Airlines)

One-way from

$173
(Kiwi.com)
From Lambert-St Louis to Ottawa
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One-way flight from Lambert-St Louis to Ottawa
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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 agosto 14, 2025.

This Kiwi.com deal was found by Cheapflights users on 8/12. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/261:57 pmSTL - YOW
1 stop26h 00mMultiple Airlines
vie. 10/37:00 amYOW - STL
2 stops14h 37mMultiple Airlines
Deal found 8/12$433
This Kiwi.com deal was found by Cheapflights users on 8/12. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/121:57 pmSTL - YOW
1 stop26h 00mMultiple Airlines
mar. 9/234:25 pmYOW - STL
2 stops42h 15mMultiple Airlines
Deal found 8/12$442
This United Airlines deal was found by Cheapflights users on 8/12. 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.
mar. 9/27:04 pmSTL - YOW
1 stop21h 02mUnited Airlines
mié. 9/106:33 amYOW - STL
1 stop8h 46mUnited Airlines
Deal found 8/12$607
This United Airlines deal was found by Cheapflights users on 8/12. 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.
vie. 9/123:20 pmSTL - YOW
1 stop24h 46mUnited Airlines
mar. 9/236:33 amYOW - STL
1 stop10h 11mUnited Airlines
Deal found 8/12$644
This United Airlines deal was found by Cheapflights users on 8/13. 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.
dom. 8/313:20 pmSTL - YOW
1 stop21h 44mUnited Airlines
jue. 9/46:33 amYOW - STL
1 stop10h 11mUnited Airlines
Deal found 8/13$736
This United Airlines deal was found by Cheapflights users on 8/12. 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.
vie. 9/266:30 amSTL - YOW
2 stops6h 56mUnited Airlines
vie. 10/310:25 amYOW - STL
2 stops10h 17mUnited Airlines
Deal found 8/12$800
This Kiwi.com deal was found by Cheapflights users on 8/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 8/276:00 amSTL - YOW
2 stops22h 58mMultiple Airlines
sáb. 8/303:50 pmYOW - STL
1 stop18h 50mMultiple Airlines
Deal found 8/13$810
This United deal was found by Cheapflights users on 8/12. 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.
vie. 12/511:50 amSTL - YOW
1 stop9h 06mMultiple Airlines
dom. 12/79:15 amYOW - STL
1 stop7h 14mMultiple Airlines
Deal found 8/12$811
This United Airlines deal was found by Cheapflights users on 8/12. 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.
vie. 12/51:00 pmSTL - YOW
1 stop7h 18mUnited Airlines
dom. 12/75:15 amYOW - STL
2 stops16h 42mUnited Airlines
Deal found 8/12$817

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 agosto 14, 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

vie. 9/26

1:57 pm-4:57 pm

1 stop26h 00m

Ottawa

vie. 10/3

7:00 am-8:37 pm

2 stops14h 37m

$433

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

vie. 9/12

1:57 pm-4:57 pm

1 stop26h 00m

Ottawa

mar. 9/23

4:25 pm-9:40 am

2 stops42h 15m

$442

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

mar. 9/2

7:04 pm-5:06 pm

1 stop21h 02m

Ottawa

mié. 9/10

6:33 am-2:19 pm

1 stop8h 46m

$607

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

vie. 9/12

3:20 pm-5:06 pm

1 stop24h 46m

Ottawa

mar. 9/23

6:33 am-3:44 pm

1 stop10h 11m

$644

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

vie. 9/26

3:23 pm-5:06 pm

1 stop24h 43m

Ottawa

vie. 10/3

5:25 pm-12:28 pm

1 stop20h 03m

$644

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

dom. 8/31

3:20 pm-2:04 pm

1 stop21h 44m

Ottawa

jue. 9/4

6:33 am-3:44 pm

1 stop10h 11m

$736

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

mié. 8/27

6:00 am-5:58 am

2 stops22h 58m

Ottawa

sáb. 8/30

3:50 pm-9:40 am

1 stop18h 50m

$810

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

vie. 12/5

11:50 am-9:56 pm

1 stop9h 06m

Ottawa

dom. 12/7

9:15 am-3:29 pm

1 stop7h 14m

$811

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

lun. 9/15

7:55 pm-4:57 pm

2 stops20h 02m

$173

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

sáb. 10/11

7:00 pm-5:20 pm

1 stop21h 20m

$177

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/14

Showing 1-10 of 16 results
1
2

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.

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 agosto 14, 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
8,916 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Crew

8.1

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??
United Airlines
7.4
Good
8,916 reviews
United Airlines
7.4
Good
8,916 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Crew

8.1

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??
Air Canada
7.1
Good
9,949 reviews
United Airlines
7.4
Good
8,916 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Crew

8.1

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??

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.

  • 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 $436.

  • 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

Browse thousands of different options on Cheapflights for your next trip

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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 agosto 14, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$330Average$812FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$436Average$822FlexibilityNo cancel feeOn-time69%

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