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Cheap flights from Ottawa to St. Louis from C$ 360

YOW — STL
7 Oct — 14 Oct1
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

Thu 24/92:45 p.m. -
1 stop4h 56m
Mon 28/912:10 p.m. -
1 stop6h 35m
Deal found 2/9C$ 683
Thu 24/95:20 p.m. -
1 stop5h 01m
Mon 28/97:30 a.m. -
1 stop14h 05m
Deal found 3/9C$ 697
Mon 12/102:50 p.m. -
1 stop4h 51m
Sun 18/108:55 a.m. -
1 stop5h 15m
Deal found 6/9C$ 707
Sat 26/910:00 a.m. -
1 stop5h 00m
Sat 10/102:40 p.m. -
1 stop5h 40m
Deal found 4/9C$ 711
Mon 12/106:50 a.m. -
2 stops17h 23m
Sun 18/104:30 p.m. -
1 stop30h 15m
Deal found 6/9C$ 761
Sat 26/92:52 p.m. -
2 stops9h 07m
Sat 10/107:30 a.m. -
1 stop8h 08m
Deal found 4/9C$ 786
Mon 5/105:20 p.m. -
1 stop5h 01m
Mon 12/101:29 p.m. -
1 stop7h 06m
Deal found 7/9C$ 804
Mon 12/105:10 a.m. -
2 stops8h 03m
Sun 18/106:00 a.m. -
2 stops10h 10m
Deal found 6/9C$ 827

Find flight deals from Ottawa to St. Louis

Round-trip from

C$ 683

One-way from

C$ 360

Popular in

August

Cheapest in

May

Average price

C$ 487
Air Canada
  • Air Canada
  • 24/9-28/9
  • 2 total stops
  • 11h 31m total
  • Ottawa to St. Louis
Search Deals
1/10-31/12
  • 1/10-31/12
  • 3 total stops
  • 29h 15m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 0% potential increase in price (C$ 8 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease (C$ 60 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in September 2026
Search Deals

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

Thu 1/10

8:55 a.m.-1:10 p.m.

3 stops29h 15m

Lambert-St Louis

Wed 31/12

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

Nonstop0h 00m

C$ 360
Quickest round-trip

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Thu 1/10

2:50 p.m.-6:41 p.m.

1 stop4h 51m

Lambert-St Louis

Wed 31/12

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

Nonstop0h 00m

C$ 379

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Sat 24/10

7:00 a.m.-11:13 p.m.

1 stop17h 13m

Lambert-St Louis

Wed 31/12

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

Nonstop0h 00m

C$ 429

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Sat 24/10

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

2 stops16h 16m

Lambert-St Louis

Wed 31/12

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

Nonstop0h 00m

C$ 443

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Thu 24/9

2:45 p.m.-6:41 p.m.

1 stop4h 56m

Lambert-St Louis

Mon 28/9

12:10 p.m.-7:45 p.m.

1 stop6h 35m

C$ 683

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Thu 24/9

5:20 p.m.-9:21 p.m.

1 stop5h 01m

Lambert-St Louis

Mon 28/9

7:30 a.m.-10:35 p.m.

1 stop14h 05m

C$ 697

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Mon 12/10

6:50 a.m.-11:13 p.m.

2 stops17h 23m

Lambert-St Louis

Sun 18/10

4:30 p.m.-11:45 p.m.

1 stop30h 15m

C$ 761

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Sat 26/9

6:00 a.m.-2:16 p.m.

2 stops9h 16m

Lambert-St Louis

Sat 10/10

9:04 a.m.-6:55 p.m.

2 stops8h 51m

C$ 786

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Mon 5/10

2:52 p.m.-9:21 p.m.

2 stops7h 29m

Lambert-St Louis

Mon 12/10

9:04 a.m.-9:35 p.m.

1 stop11h 31m

C$ 867

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Thu 24/9

6:55 a.m.-3:54 p.m.

2 stops9h 59m

Lambert-St Louis

Mon 28/9

7:05 a.m.-12:20 a.m.

2 stops16h 15m

C$ 873

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/9

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

What’s the top layover airport for flights from Ottawa to St. Louis?

Toronto (YYZ) – chosen by Cheapflights users on 67% of one-stop itineraries from Ottawa to St. Louis on Cheapflights.

What’s the cheapest layover airport for flights from Ottawa to St. Louis?

Newark (EWR) is the most affordable 1-stop option, with an average round-trip price of C$ 481.

What’s the fastest layover option from Ottawa to St. Louis?

Flights via Chicago (ORD) have the shortest average one-way travel time for 1-stop routes: 5h 16m.

Which airport typically offers the quickest layover for flights from Ottawa to St. Louis?

Flights via Chicago (ORD) offer the fastest connection on this route, with an average layover time of 1h 05m.

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
7.4
Good
10,173 reviews
Check prices

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

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
10,173 reviews
United Airlines
7.4
Good
10,173 reviews
Check prices

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

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
11,595 reviews
United Airlines
7.4
Good
10,173 reviews
Check prices

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

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 4h 56m. Fly via Air Canada 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$ 398, 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 42% 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

Browse thousands of different options on Cheapflights for your next trip

Top 2 airlines flying from Ottawa to St. Louis

AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 398AverageC$ 686FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 407AverageC$ 652FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

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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.

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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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