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Cheap flights from Ottawa to St. Louis from $203

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ottawa to St. Louis departing on 6/15. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Find the cheapest flights from Ottawa to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Air Canada Logo
2:40 pm - 8:25 pm
YOW
-
STL
6h 45m
1 stop
Air Canada Logo
7:05 am - 1:05 pm
STL
-
YOW
5h 00m
1 stop
$348Air Canada
Sat, May 23 - Sun, May 24
United Airlines Logo
6:25 am - 3:46 pm
YOW
-
STL
10h 21m
1 stop
United Airlines Logo
6:00 am - 4:38 pm
STL
-
YOW
9h 38m
1 stop
$353United Airlines
Tue, Jun 2 - Wed, Jun 3
Air Canada Logo
2:40 pm - 8:25 pm
YOW
-
STL
6h 45m
1 stop
Air Canada Logo
7:05 am - 1:05 pm
STL
-
YOW
5h 00m
1 stop
$371Air Canada
Sat, May 23 - Sun, May 24
United Airlines Logo
5:25 pm - 9:21 pm
YOW
-
STL
4h 56m
1 stop
United Airlines Logo
6:00 am - 9:35 pm
STL
-
YOW
14h 35m
1 stop
$372United Airlines
Tue, Jun 2 - Wed, Jun 3
United Airlines Logo
2:52 pm - 9:21 pm
YOW
-
STL
7h 29m
2 stops
United Airlines Logo
6:00 am - 4:38 pm
STL
-
YOW
9h 38m
1 stop
$373United Airlines
Tue, Jun 2 - Wed, Jun 3
Air Canada Logo
2:40 pm - 8:25 pm
YOW
-
STL
6h 45m
1 stop
Air Canada Logo
7:05 am - 1:05 pm
STL
-
YOW
5h 00m
1 stop
$379Air Canada
Tue, May 19 - Sat, May 23
United Airlines Logo
6:05 am - 3:46 pm
YOW
-
STL
10h 41m
2 stops
United Airlines Logo
5:33 pm - 2:11 pm
STL
-
YOW
19h 38m
2 stops
$407United Airlines
Sat, Jul 4 - Mon, Jul 6
Air Canada Logo
11:15 am - 9:23 pm
YOW
-
STL
11h 08m
2 stops
Air Canada Logo
7:05 am - 1:05 pm
STL
-
YOW
5h 00m
1 stop
$415Air Canada
Sat, May 23 - Sun, May 24
Delta Logo
6:55 am - 1:10 pm
YOW
-
STL
7h 15m
2 stops
Delta Logo
1:27 pm - 12:20 am
STL
-
YOW
9h 53m
2 stops
$431Delta
Tue, Jun 2 - Wed, Jun 3
United Airlines Logo
5:05 am - 3:46 pm
YOW
-
STL
11h 41m
2 stops
United Airlines Logo
6:00 am - 9:35 pm
STL
-
YOW
14h 35m
1 stop
$434United Airlines
Fri, May 29 - Sun, May 31

United Airlines flights from Ottawa to St. Louis

Our best United Airlines deals on Ottawa to St. Louis flight tickets
United Airlines
Jun 2
YOW6:25 amOttawa
10h 21m
1 stop
STL3:46 pmLambert-St Louis
Jun 3
STL6:00 amLambert-St Louis
9h 38m
1 stop
YOW4:38 pmOttawa
$353
United Airlines
Jun 2
YOW5:25 pmOttawa
4h 56m
1 stop
STL9:21 pmLambert-St Louis
Jun 3
STL6:00 amLambert-St Louis
14h 35m
1 stop
YOW9:35 pmOttawa
$372
United Airlines
Jun 2
YOW2:52 pmOttawa
7h 29m
2 stops
STL9:21 pmLambert-St Louis
Jun 3
STL6:00 amLambert-St Louis
9h 38m
1 stop
YOW4:38 pmOttawa
$373

Air Canada flights from Ottawa to St. Louis

Our best Air Canada deals on Ottawa to St. Louis flight tickets
Air Canada
May 23
YOW2:40 pmOttawa
6h 45m
1 stop
STL8:25 pmLambert-St Louis
May 24
STL7:05 amLambert-St Louis
5h 00m
1 stop
YOW1:05 pmOttawa
$348
Air Canada
May 23
YOW2:40 pmOttawa
6h 45m
1 stop
STL8:25 pmLambert-St Louis
May 24
STL7:05 amLambert-St Louis
5h 00m
1 stop
YOW1:05 pmOttawa
$371
Air Canada
May 19
YOW2:40 pmOttawa
6h 45m
1 stop
STL8:25 pmLambert-St Louis
May 23
STL7:05 amLambert-St Louis
5h 00m
1 stop
YOW1:05 pmOttawa
$379

momondo 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, momondo users made 832,500 searches. Data last updated May 8, 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
Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/23

2:40 pm-8:25 pm

1 stop6h 45m

Lambert-St Louis

Sun 5/24

7:05 am-1:05 pm

1 stop5h 00m

$348

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 6/2

6:25 am-3:46 pm

1 stop10h 21m

Lambert-St Louis

Wed 6/3

6:00 am-4:38 pm

1 stop9h 38m

$353

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/23

2:40 pm-8:25 pm

1 stop6h 45m

Lambert-St Louis

Sun 5/24

7:05 am-1:05 pm

1 stop5h 00m

$371

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 6/2

5:25 pm-9:21 pm

1 stop4h 56m

Lambert-St Louis

Wed 6/3

6:00 am-9:35 pm

1 stop14h 35m

$372

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 6/2

2:52 pm-9:21 pm

2 stops7h 29m

Lambert-St Louis

Wed 6/3

6:00 am-4:38 pm

1 stop9h 38m

$373

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 5/19

2:40 pm-8:25 pm

1 stop6h 45m

Lambert-St Louis

Sat 5/23

7:05 am-1:05 pm

1 stop5h 00m

$379

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 7/4

6:05 am-3:46 pm

2 stops10h 41m

Lambert-St Louis

Mon 7/6

5:33 pm-2:11 pm

2 stops19h 38m

$407

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/23

11:15 am-9:23 pm

2 stops11h 08m

Lambert-St Louis

Sun 5/24

7:05 am-1:05 pm

1 stop5h 00m

$415

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 6/2

6:55 am-1:10 pm

2 stops7h 15m

Lambert-St Louis

Wed 6/3

1:27 pm-12:20 am

2 stops9h 53m

$431

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 5/29

5:05 am-3:46 pm

2 stops11h 41m

Lambert-St Louis

Sun 5/31

6:00 am-9:35 pm

1 stop14h 35m

$434

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 16 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Ottawa to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between Ottawa and St. Louis?

What is the cheapest month to fly to St. Louis?

In general, February is the cheapest month to fly from Ottawa to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $0. The month of April is another great option to travel to St. Louis, with average flight prices from Ottawa averaging around $394.

When to book flights from Ottawa to St. Louis

Are you open to changing your travel dates? Check out the ideal times to fly from Ottawa to St. Louis according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Ottawa to St. Louis (YOW to STL) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ottawa to St. Louis

Fastest flight time

4h 56m

Direct flights

None
The fastest flight from Ottawa to St. Louis takes 4h 56m
There are no direct flights from Ottawa to St. Louis. There are no popular flight routes from Ottawa to St. Louis.
Search flight deals

Frequently asked questions about flying from Ottawa to St. Louis

  • How far is Ottawa to Lambert-St Louis by plane?

    The straight-line distance from Ottawa to Lambert-St Louis is 877.2 mi. By plane, this route typically takes 4h 56m.

  • When did momondo last update prices for flights from Ottawa Airport to Lambert-St Louis Airport?

    Prices for flights from Ottawa Airport to Lambert-St Louis Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Ottawa Airport to Lambert-St Louis Airport?

  • How old do you have to be to fly from Ottawa Airport to Lambert-St Louis Airport?

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ottawa Airport to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from Ottawa to St. Louis?

Best airlines flying from Ottawa to St. Louis

Compare and see reviews for airlines that fly from Ottawa to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
Air CanadaPriceFrom $285Free CancellationRating
7.1
11,002 reviews
Search Air Canada flights

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Hermann
Fairview Heights
Maryland Heights
O'Fallon
Florissant
St. Peters
Collinsville
Wentzville
Alton
Fenton
Farmington
Festus
Clayton
Eureka
Litchfield
Edwardsville
Shrewsbury
Grafton

Why use momondo?

Why should I use momondo to find a flight deal from Ottawa to St. Louis?

Finding the right flight to St. Louis from Ottawa is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to St. Louis quick and easy, saving you time and money.

Can I find flights from Ottawa to St. Louis with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to St. Louis from Ottawa with this policy.

How can momondo help me find flights from Ottawa to St. Louis?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Ottawa to St. Louis.

I’m not ready to book a flight from Ottawa to St. Louis right now. Can momondo alert me if prices change?

If you are simply researching potential flights to St. Louis, momondo offers a useful price alert feature which will track prices for flights to St. Louis from Ottawa and alert you when they change.

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