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Cheap flights from Ottawa to St. Louis from C$ 317

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 24/7. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
12 Jul — 19 Jul1
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 12 June 2026.

Mon 14/126:00 p.m.
YOW
-
STL
1 stop6h 25m
United Airlines
Tue 15/1210:23 a.m.
STL
-
YOW
1 stop5h 51m
United Airlines
Deal found 11/6C$ 524
Thu 9/73:10 p.m.
YOW
-
STL
1 stop4h 32m
Air Canada
Wed 15/78:55 a.m.
STL
-
YOW
1 stop5h 15m
Air Canada
Deal found 10/6C$ 527
Fri 3/76:25 a.m.
YOW
-
STL
1 stop6h 46m
United Airlines
Tue 7/711:25 a.m.
STL
-
YOW
1 stop4h 42m
United Airlines
Deal found 9/6C$ 546
Tue 1/95:20 p.m.
YOW
-
STL
1 stop5h 40m
United Airlines
Wed 2/99:30 a.m.
STL
-
YOW
2 stops10h 45m
United Airlines
Deal found 8/6C$ 557
Wed 1/712:00 p.m.
YOW
-
STL
2 stops12h 44m
United Airlines
Sun 5/76:50 a.m.
STL
-
YOW
2 stops7h 20m
United Airlines
Deal found 9/6C$ 568
Fri 26/67:00 a.m.
YOW
-
STL
1 stop6h 21m
Air Canada
Sun 28/61:20 p.m.
STL
-
YOW
1 stop6h 51m
Air Canada
Deal found 6/6C$ 584
Tue 30/67:00 a.m.
YOW
-
STL
1 stop6h 21m
Air Canada
Mon 13/72:40 p.m.
STL
-
YOW
1 stop5h 35m
Air Canada
Deal found 8/6C$ 595
Tue 1/99:00 a.m.
YOW
-
STL
1 stop6h 02m
Air Canada
Wed 2/98:55 a.m.
STL
-
YOW
1 stop5h 15m
Air Canada
Deal found 7/6C$ 601

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 12 June 2026.

Round-trip from

C$ 527

One-way from

C$ 317

Popular in

August

Cheapest in

May

Average price

C$ 573
Air Canada
  • Air Canada
  • 9/7-15/7
  • 2 total stops
  • 9h 47m total
  • Ottawa to St. Louis
Search Deals
Air Canada
  • Air Canada
  • 24/7
  • 1 total stop
  • 6h 02m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 8% potential increase in price (C$ 86 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (C$ 44 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 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 12 June 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

Tue 1/9

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

1 stop6h 01m

Lambert-St Louis

Wed 2/9

7:25 a.m.-9:35 p.m.

1 stop13h 10m

C$ 546

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 3/7

6:25 a.m.-10:34 a.m.

1 stop5h 09m

Lambert-St Louis

Tue 7/7

6:01 a.m.-4:38 p.m.

1 stop9h 37m

C$ 546

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 7/7

5:50 p.m.-11:36 p.m.

1 stop6h 46m

Lambert-St Louis

Tue 14/7

6:01 a.m.-4:38 p.m.

1 stop9h 37m

C$ 546

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 1/7

6:25 a.m.-12:11 p.m.

1 stop6h 46m

Lambert-St Louis

Sun 5/7

6:50 a.m.-5:10 p.m.

2 stops9h 20m

C$ 557
Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 1/9

9:00 a.m.-2:02 p.m.

1 stop6h 02m

Lambert-St Louis

Wed 2/9

8:55 a.m.-3:10 p.m.

1 stop5h 15m

C$ 601

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 30/6

6:00 a.m.-3:46 p.m.

2 stops10h 46m

Lambert-St Louis

Mon 13/7

2:40 p.m.-9:15 p.m.

1 stop5h 35m

C$ 613
Cheapest one-way
Quickest one-way

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 24/7

9:00 a.m.-2:02 p.m.

1 stop6h 02m

C$ 317

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 24/7

7:00 a.m.-8:57 a.m.

2 stops26h 57m

C$ 338

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/6

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 12 June 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
9,809 reviews
Check prices

Crew

8.1

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Reviews

1 / 20
4.0
Okay

Dynasty,May 2026

LAX - EWR

The food wasn’t nice - Hosts were not that kind.
United Airlines
7.4
Good
9,809 reviews
United Airlines
7.4
Good
9,809 reviews
Check prices

Crew

8.1

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Reviews

1 / 20
4.0
Okay

Dynasty,May 2026

LAX - EWR

The food wasn’t nice - Hosts were not that kind.
Air Canada
7.1
Good
11,164 reviews
United Airlines
7.4
Good
9,809 reviews
Check prices

Crew

8.1

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Reviews

1 / 20
4.0
Okay

Dynasty,May 2026

LAX - EWR

The food wasn’t nice - Hosts were not that kind.

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 United Airlines to get the fastest option. Airlines will cover a distance of 1413 km.

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

    United Airlines, at C$ 402, 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 40% 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 12 June 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 402AverageC$ 698FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 411AverageC$ 883FlexibilityNo 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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