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Cheap flights from Ottawa to St. Louis from C$ 345

YOW — STL
25 Nov — 2 Dec1
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

Wed 9/128:00 a.m. -
1 stop17h 12m
Wed 16/126:20 p.m. -
2 stops21h 55m
Deal found 25/10C$ 718
Thu 26/117:00 a.m. -
3 stops29h 03m
Mon 30/116:35 p.m. -
3 stops22h 21m
Deal found 22/10C$ 857
Sat 21/118:00 a.m. -
1 stop16h 59m
Sat 28/116:05 p.m. -
2 stops22h 10m
Deal found 24/10C$ 915
Tue 29/1210:05 a.m. -
1 stop6h 21m
Mon 4/14:05 p.m. -
1 stop5h 50m
Deal found 25/10C$ 920
Sat 21/113:10 p.m. -
1 stop8h 44m
Sat 28/118:30 a.m. -
2 stops12h 26m
Deal found 22/10C$ 940
Tue 29/126:00 a.m. -
2 stops12h 08m
Mon 4/14:05 p.m. -
1 stop5h 50m
Deal found 25/10C$ 945

Find flight deals from Ottawa to St. Louis

Round-trip from

C$ 718

One-way from

C$ 345

Popular in

August

Cheapest in

May

Average price

C$ 923
9/12-16/12
  • 9/12-16/12
  • 3 total stops
  • 39h 07m total
  • Ottawa to St. Louis
Search Deals
29/1-31/12
  • 29/1-31/12
  • 3 total stops
  • 37h 04m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 2% potential increase in price (C$ 25 potential increase over avg. RT price).
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Cheapest flight prices on average. 7% potential price decrease (C$ 63 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 2026
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Cheapflights Fare Finder

 
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 Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Fri 29/1

12:00 p.m.-12:04 a.m.

3 stops37h 04m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 345
Quickest round-trip

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Fri 29/1

6:15 a.m.-5:50 p.m.

1 stop12h 35m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 524

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Wed 9/12

8:00 a.m.-12:12 a.m.

1 stop17h 12m

Lambert-St Louis

Wed 16/12

6:20 p.m.-5:15 p.m.

2 stops21h 55m

C$ 718

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Sat 21/11

3:10 p.m.-10:54 p.m.

1 stop8h 44m

Lambert-St Louis

Sat 28/11

6:00 a.m.-9:16 p.m.

1 stop14h 16m

C$ 940

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Tue 29/12

6:00 a.m.-5:08 p.m.

2 stops12h 08m

Lambert-St Louis

Mon 4/1

4:05 p.m.-10:55 p.m.

1 stop5h 50m

C$ 945

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Sat 13/2

6:15 a.m.-6:06 p.m.

1 stop12h 51m

Lambert-St Louis

Sat 20/2

3:21 p.m.-9:26 p.m.

1 stop5h 05m

C$ 961

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Tue 8/12

6:15 a.m.-7:26 p.m.

1 stop14h 11m

Lambert-St Louis

Fri 11/12

6:30 a.m.-2:09 p.m.

1 stop6h 39m

C$ 964

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Thu 26/11

3:10 p.m.-8:53 a.m.

1 stop18h 43m

Lambert-St Louis

Mon 30/11

4:05 p.m.-9:50 p.m.

1 stop4h 45m

C$ 968

Flights are sorted by cheapest round-trip flights first.

Deals found on 24/10

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

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?

Airfare is typical for this route at the moment.

Ottawa to St. Louis flights typically cost between C$ 693 and C$ 918 in December.
The cheapest round-trip price found within the last 5 days was C$ 718 on Multiple Airlines (9 Dec-16 Dec).

Reviews of airlines servicing St. Louis

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
7.3
Good
10,440 reviews
Check prices

Food

6.7

Overall

7.3

Crew

8.1

Entertainment

7.1

Boarding

7.7

Comfort

7.3

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
7.3
Good
10,440 reviews
United Airlines
7.3
Good
10,440 reviews
Check prices

Food

6.7

Overall

7.3

Crew

8.1

Entertainment

7.1

Boarding

7.7

Comfort

7.3

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
11,815 reviews
United Airlines
7.3
Good
10,440 reviews
Check prices

Food

6.7

Overall

7.3

Crew

8.1

Entertainment

7.1

Boarding

7.7

Comfort

7.3

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

  • How long is the flight from Ottawa to St. Louis?

    There are many flights that can get you from Ottawa to St. Louis in 8h 44m. 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$ 403, 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

AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 403AverageC$ 510FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 412AverageC$ 890FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

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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.

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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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