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Cheap flights from Ottawa to St. Louis from C$ 352

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 18/8. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
22 Aug — 29 Aug1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ottawa to St. Louis

Enter your travel dates to find the best prices.

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 23 July 2026.

Sat 5/97:00 a.m.
YOW
-
STL
1 stop10h 11m
Multiple Airlines
Sun 13/910:35 a.m.
STL
-
YOW
2 stops27h 40m
Multiple Airlines
Deal found 20/7C$ 655
Sat 19/96:55 a.m.
YOW
-
STL
2 stops9h 19m
Delta
Wed 23/92:30 p.m.
STL
-
YOW
2 stops8h 50m
Delta
Deal found 20/7C$ 723
Wed 12/83:10 p.m.
YOW
-
STL
2 stops8h 49m
United Airlines
Wed 19/81:36 p.m.
STL
-
YOW
2 stops9h 18m
United Airlines
Deal found 20/7C$ 726
Sat 19/96:00 a.m.
YOW
-
STL
3 stops10h 38m
United Airlines
Wed 23/912:59 p.m.
STL
-
YOW
1 stop7h 36m
United Airlines
Deal found 22/7C$ 733
Wed 25/116:00 a.m.
YOW
-
STL
2 stops11h 56m
United Airlines
Sun 29/116:00 a.m.
STL
-
YOW
1 stop7h 09m
United Airlines
Deal found 20/7C$ 762
Sun 18/106:25 a.m.
YOW
-
STL
1 stop10h 18m
United Airlines
Sat 24/108:00 a.m.
STL
-
YOW
1 stop12h 35m
United Airlines
Deal found 21/7C$ 772
Sat 19/92:35 p.m.
YOW
-
STL
2 stops9h 24m
Air Canada
Wed 23/910:53 a.m.
STL
-
YOW
1 stop5h 23m
Air Canada
Deal found 18/7C$ 815
Thu 15/106:50 a.m.
YOW
-
STL
2 stops10h 33m
Delta
Sun 18/106:40 a.m.
STL
-
YOW
2 stops9h 55m
Delta
Deal found 20/7C$ 855
Thu 6/86:25 a.m.
YOW
-
STL
1 stop5h 09m
United Airlines
Sat 8/88:43 a.m.
STL
-
YOW
1 stop4h 34m
United Airlines
Deal found 21/7C$ 871

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 23 July 2026.

Round-trip from

C$ 655

One-way from

C$ 352

Popular in

March

Cheapest in

May

Average price

C$ 496
5/9-13/9
  • 5/9-13/9
  • 3 total stops
  • 37h 51m total
  • Ottawa to St. Louis
Search Deals
Air Canada
  • Air Canada
  • 18/8
  • 1 total stop
  • 5h 02m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (C$ 150 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (C$ 52 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2026
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 629,999 searches. Data last updated 23 July 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

Cheapest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 19/9

6:55 a.m.-3:14 p.m.

2 stops9h 19m

Lambert-St Louis

Wed 23/9

2:30 p.m.-12:20 a.m.

2 stops8h 50m

C$ 723

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 12/8

10:37 a.m.-3:38 p.m.

1 stop6h 01m

Lambert-St Louis

Wed 19/8

7:25 a.m.-1:59 p.m.

1 stop5h 34m

C$ 726

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 25/11

4:36 p.m.-11:09 p.m.

1 stop7h 33m

Lambert-St Louis

Sun 29/11

6:00 a.m.-2:09 p.m.

1 stop7h 09m

C$ 726
Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 19/9

6:00 a.m.-9:39 a.m.

1 stop4h 39m

Lambert-St Louis

Wed 23/9

10:53 a.m.-5:16 p.m.

1 stop5h 23m

C$ 726

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 15/10

6:05 a.m.-9:21 p.m.

2 stops16h 16m

Lambert-St Louis

Sun 18/10

8:00 a.m.-9:35 p.m.

1 stop12h 35m

C$ 726

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sun 6/9

10:00 a.m.-7:16 p.m.

2 stops10h 16m

Lambert-St Louis

Sun 13/9

12:59 p.m.-9:35 p.m.

1 stop7h 36m

C$ 733
Cheapest one-way
Quickest one-way

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 18/8

6:55 a.m.-1:14 p.m.

2 stops7h 19m

C$ 403

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 18/8

6:00 a.m.-10:00 p.m.

3 stops17h 00m

C$ 404

Flights are sorted by cheapest round-trip flights first.

Deals found on 20/7

Sorted by cheapest first

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

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 23 July 2026.
Check out reviews from past customers who have flown with United Airlines and Air Canada from Ottawa to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
10,026 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Crew

8.1

Boarding

7.7

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats
United Airlines
7.4
Good
10,026 reviews
United Airlines
7.4
Good
10,026 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Crew

8.1

Boarding

7.7

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats
Air Canada
7.1
Good
11,373 reviews
United Airlines
7.4
Good
10,026 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Crew

8.1

Boarding

7.7

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats

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?

    There are many flights that can get you from Ottawa to St. Louis in 6h 01m. Fly via Delta or United Airlines to get the fastest option. Airlines will cover a distance of 1413 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    United Airlines, at C$ 406, was found to be the cheapest airline from Ottawa to St. Louis. An alternate airline flying to your destination would be Air Canada. United Airlines is currently priced 41% below the average price you’ll pay for this route.

  • 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.

See more FAQs

Travelling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Chesterfield

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Top 2 airlines flying from Ottawa to St. Louis

Discover the top 2 airlines 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 629,999 searches. Data last updated 23 July 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 406AverageC$ 704FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 414AverageC$ 891FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Ottawa to St. Louis?

When you search for this flight from Ottawa to St. Louis, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Ottawa to St. Louis?

Cheapflights helps you find that perfect flight to St. Louis from Ottawa by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Ottawa to St. Louis with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Ottawa to St. Louis flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Ottawa to St. Louis become cheaper?

Yes! Start tracking prices for Ottawa to St. Louis flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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