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$179+ 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 6/25. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
Jun 11 — Jun 181
Thu 6/11
Thu 6/18
1 adult, Economy
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Cheap 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 May 12, 2026.

This United Airlines deal was found by Cheapflights users on 5/11. 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.
Sat 9/269:23 am
STL
-
YOW
1 stop6h 58m
United Airlines
Sat 10/36:52 am
YOW
-
STL
1 stop8h 26m
United Airlines
Deal found 5/11$409
This Air Canada deal was found by Cheapflights users on 5/11. 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.
Sat 5/307:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Wed 6/32:40 pm
YOW
-
STL
1 stop6h 45m
Air Canada
Deal found 5/11$421
This Air Canada deal was found by Cheapflights users on 5/11. 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 6/92:15 pm
STL
-
YOW
1 stop6h 01m
Air Canada
Tue 6/162:35 pm
YOW
-
STL
1 stop6h 50m
Air Canada
Deal found 5/11$423
This United Airlines deal was found by Cheapflights users on 5/11. 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.
Mon 6/87:22 am
STL
-
YOW
1 stop8h 45m
United Airlines
Mon 6/155:50 pm
YOW
-
STL
1 stop6h 45m
United Airlines
Deal found 5/11$424
This United Airlines deal was found by Cheapflights users on 5/11. 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 6/95:29 pm
STL
-
YOW
2 stops15h 34m
United Airlines
Tue 6/166:25 am
YOW
-
STL
1 stop6h 46m
United Airlines
Deal found 5/11$434
This Air Canada deal was found by Cheapflights users on 5/11. 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.
Sat 9/269:23 am
STL
-
YOW
1 stop10h 51m
Air Canada
Sat 10/39:55 am
YOW
-
STL
2 stops7h 31m
Air Canada
Deal found 5/11$490
This United Airlines deal was found by Cheapflights users on 5/9. 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.
Sat 5/306:00 am
STL
-
YOW
1 stop6h 59m
United Airlines
Wed 6/36:00 am
YOW
-
STL
2 stops10h 46m
United Airlines
Deal found 5/9$496
This United Airlines deal was found by Cheapflights users on 5/9. 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 6/2311:25 am
STL
-
YOW
2 stops9h 40m
United Airlines
Tue 6/306:05 am
YOW
-
STL
2 stops10h 41m
United Airlines
Deal found 5/9$502

Find 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 May 12, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$409
(United Airlines)

One-way from

$179
(United Airlines)

Popular in

August

Cheapest in

March

Average price

$441
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. 18% potential increase in price ($139 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($31 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 2026
Search Deals

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 May 12, 2026.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 9/26

9:23 am-5:21 pm

1 stop6h 58m

Ottawa

Sat 10/3

6:52 am-2:18 pm

1 stop8h 26m

$409
Quickest round-trip

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 5/30

7:05 am-1:05 pm

1 stop5h 00m

Ottawa

Wed 6/3

2:40 pm-8:25 pm

1 stop6h 45m

$421

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 6/8

7:22 am-5:07 pm

1 stop8h 45m

Ottawa

Mon 6/15

5:50 pm-11:35 pm

1 stop6h 45m

$424

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 6/23

1:20 pm-9:11 pm

1 stop6h 51m

Ottawa

Tue 6/30

7:00 am-12:21 pm

1 stop6h 21m

$483

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 5/30

6:00 am-1:59 pm

1 stop6h 59m

Ottawa

Wed 6/3

6:00 am-3:46 pm

2 stops10h 46m

$496

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 6/23

12:55 pm-11:54 pm

1 stop9h 59m

Ottawa

Tue 6/30

6:05 am-3:46 pm

2 stops10h 41m

$496

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 8/7

8:55 am-9:15 pm

1 stop11h 20m

Ottawa

Wed 8/12

2:35 pm-6:42 pm

1 stop5h 07m

$508

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 7/31

1:13 pm-9:15 pm

2 stops7h 02m

Ottawa

Sun 8/2

6:25 am-12:11 pm

1 stop6h 46m

$513
Cheapest one-way

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 7/1

7:20 am-1:59 pm

1 stop5h 39m

$183
Quickest one-way

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 7/2

11:25 am-5:07 pm

1 stop4h 42m

$183

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/10

Showing 1-10 of 18 resultsSorted by cheapest first
1
2
  • 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

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 May 12, 2026.
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
9,701 reviews

Overall

7.4

Comfort

7.3

Entertainment

7.1

Boarding

7.7

Crew

8.1

Food

6.6

Reviews

1 / 20
8.0
Excellent

Anonymous,Apr 2026

DFW - EWR

The flight was on time. Crew was friendly. Will fly again. The seats was comfortable.
United Airlines
7.4
Good
9,701 reviews
United Airlines
7.4
Good
9,701 reviews

Overall

7.4

Comfort

7.3

Entertainment

7.1

Boarding

7.7

Crew

8.1

Food

6.6

Reviews

1 / 20
8.0
Excellent

Anonymous,Apr 2026

DFW - EWR

The flight was on time. Crew was friendly. Will fly again. The seats was comfortable.
Air Canada
7.1
Good
11,020 reviews
United Airlines
7.4
Good
9,701 reviews

Overall

7.4

Comfort

7.3

Entertainment

7.1

Boarding

7.7

Crew

8.1

Food

6.6

Reviews

1 / 20
8.0
Excellent

Anonymous,Apr 2026

DFW - EWR

The flight was on time. Crew was friendly. Will fly again. The seats was comfortable.

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 5h. United Airlines provides one of the quickest options available for as low as $421. 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 $139, 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 $304. Air Canada is 77% 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.

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 May 12, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$139Average$697FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$304Average$754FlexibilityNo cancel feeOn-time69%

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