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Cheap flights from St. Louis to Ottawa from $156

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Ottawa departing on 12/5. 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 St. Louis to Ottawa

Cheap round-trip flights

Enter your travel dates to find the best prices.
Air Canada Logo
4:05 pm - 11:08 pmSTL-YOW
6h 03m1 stop
Air Canada Logo
9:15 am - 3:29 pmYOW-STL
7h 14m1 stop
$383Air Canada
Find Deal
Sun, Nov 2 - Sun, Nov 9
United Airlines Logo
7:00 am - 1:32 pmSTL-YOW
5h 32m1 stop
United Airlines Logo
7:30 pm - 10:51 amYOW-STL
16h 21m2 stops
$394United Airlines
Find Deal
Wed, Nov 19 - Wed, Nov 26
Air Canada Logo
6:43 pm - 10:26 amSTL-YOW
14h 43m1 stop
Air Canada Logo
7:15 am - 3:46 pmYOW-STL
9h 31m2 stops
$471Air Canada
Find Deal
Sun, Nov 2 - Sun, Nov 9
Delta Logo
11:39 am - 12:42 amSTL-YOW
12h 03m2 stops
Delta Logo
5:40 am - 5:09 pmYOW-STL
12h 29m2 stops
$483Delta
Find Deal
Wed, Nov 19 - Wed, Nov 26
Multiple Airlines Logo
3:53 pm - 8:05 pmSTL-YOW
51h 12m2 stops
Multiple Airlines Logo
4:20 pm - 11:57 pmYOW-STL
8h 37m1 stop
$516Multiple Airlines
Find Deal
Fri, Nov 21 - Fri, Nov 28
Delta Logo
3:59 pm - 12:42 amSTL-YOW
7h 43m2 stops
Delta Logo
5:40 am - 5:09 pmYOW-STL
12h 29m2 stops
$520Delta
Find Deal
Sun, Nov 2 - Sun, Nov 9
United Airlines Logo
6:30 am - 2:13 pmSTL-YOW
6h 43m2 stops
United Airlines Logo
5:55 pm - 11:44 pmYOW-STL
6h 49m1 stop
$562United Airlines
Find Deal
Wed, Oct 22 - Mon, Oct 27
United Airlines Logo
11:10 am - 5:06 pmSTL-YOW
4h 56m1 stop
United Airlines Logo
5:55 pm - 11:44 pmYOW-STL
6h 49m1 stop
$596United Airlines
Find Deal
Wed, Oct 22 - Mon, Oct 27
American Airlines Logo
7:16 am - 9:00 pmSTL-YOW
12h 44m2 stops
American Airlines Logo
6:45 am - 11:54 pmYOW-STL
18h 09m2 stops
$627American Airlines
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Wed, Oct 22 - Mon, Oct 27
American Airlines Logo
6:52 am - 12:39 amSTL-YOW
16h 47m3 stops
American Airlines Logo
6:45 am - 4:16 pmYOW-STL
10h 31m2 stops
$640American Airlines
Find Deal
Wed, Nov 19 - Wed, Nov 26

Air Canada flights from St. Louis to Ottawa

Our best Air Canada deals on St. Louis to Ottawa flight tickets
Air Canada
Nov 2
STL4:05 pmLambert-St Louis
6h 03m
1 stop
YOW11:08 pmOttawa
Nov 9
YOW9:15 amOttawa
7h 14m
1 stop
STL3:29 pmLambert-St Louis
$383
Find similar
Air Canada
Nov 2
STL6:43 pmLambert-St Louis
14h 43m
1 stop
YOW10:26 amOttawa
Nov 9
YOW7:15 amOttawa
9h 31m
2 stops
STL3:46 pmLambert-St Louis
$471
Find similar

United Airlines flights from St. Louis to Ottawa

Our best United Airlines deals on St. Louis to Ottawa flight tickets
United Airlines
Nov 19
STL7:00 amLambert-St Louis
5h 32m
1 stop
YOW1:32 pmOttawa
Nov 26
YOW7:30 pmOttawa
16h 21m
2 stops
STL10:51 amLambert-St Louis
$394
Find similar
United Airlines
Oct 22
STL6:30 amLambert-St Louis
6h 43m
2 stops
YOW2:13 pmOttawa
Oct 27
YOW5:55 pmOttawa
6h 49m
1 stop
STL11:44 pmLambert-St Louis
$562
Find similar
United Airlines
Oct 22
STL11:10 amLambert-St Louis
4h 56m
1 stop
YOW5:06 pmOttawa
Oct 27
YOW5:55 pmOttawa
6h 49m
1 stop
STL11:44 pmLambert-St Louis
$596
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Ottawa 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 October 8, 2025.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 11/2

4:05 pm-11:08 pm

1 stop6h 03m

Ottawa

Sun 11/9

9:15 am-3:29 pm

1 stop7h 14m

$383

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 11/19

7:00 am-1:32 pm

1 stop5h 32m

Ottawa

Wed 11/26

7:30 pm-10:51 am

2 stops16h 21m

$394

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 11/2

6:43 pm-10:26 am

1 stop14h 43m

Ottawa

Sun 11/9

7:15 am-3:46 pm

2 stops9h 31m

$471

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 11/19

11:39 am-12:42 am

2 stops12h 03m

Ottawa

Wed 11/26

5:40 am-5:09 pm

2 stops12h 29m

$483

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 11/21

3:53 pm-8:05 pm

2 stops51h 12m

Ottawa

Fri 11/28

4:20 pm-11:57 pm

1 stop8h 37m

$516

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 11/2

3:59 pm-12:42 am

2 stops7h 43m

Ottawa

Sun 11/9

5:40 am-5:09 pm

2 stops12h 29m

$520

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 10/22

6:30 am-2:13 pm

2 stops6h 43m

Ottawa

Mon 10/27

5:55 pm-11:44 pm

1 stop6h 49m

$562

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 10/22

11:10 am-5:06 pm

1 stop4h 56m

Ottawa

Mon 10/27

5:55 pm-11:44 pm

1 stop6h 49m

$596

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 10/22

7:16 am-9:00 pm

2 stops12h 44m

Ottawa

Mon 10/27

6:45 am-11:54 pm

2 stops18h 09m

$627

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 11/19

6:52 am-12:39 am

3 stops16h 47m

Ottawa

Wed 11/26

6:45 am-4:16 pm

2 stops10h 31m

$640

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 15 resultsSorted by cheapest first
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See travel insights to Ottawa from

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

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 cheapest day to depart on your flight to Ottawa?

The cheapest day to depart from St. Louis to Ottawa is on a Saturday. Travelers who choose to depart for Ottawa on a Saturday will often find tickets for as low as $407. Be sure to avoid booking your departure on a Monday as prices are generally higher than usual. According to our data, the average ticket price to Ottawa on Monday is $860.

What is the cheapest time of day to depart on your flight to Ottawa?

In the afternoon is the cheapest time of day to fly from St. Louis to Ottawa when you can find flight prices for as low as $615. Flying to Ottawa in the afternoon is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $682 on average. Flights to Ottawa from St. Louis in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

Can stopping save me money on St. Louis to Ottawa flights?

You could potentially save up to 47% on your flight if you consider stops on a St. Louis to Ottawa flight.

When to book flights from St. Louis to Ottawa

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

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

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

Direct flights

None
There are no direct flights from St. Louis to Ottawa. There are no popular flight routes from St. Louis to Ottawa.
Search flight deals

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

    There are 877.2 mi between Lambert-St Louis and Ottawa. By plane, this route typically takes 4h 56m.

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

    Prices for flights from Lambert-St Louis Airport to Ottawa Airport are updated daily.

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

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

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Ottawa Airport.

  • What documentation or ID do you need to fly to Ottawa Airport?

    The required travel and health documents for your Ottawa Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ottawa Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

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

Best airlines flying from St. Louis to Ottawa

Compare and see reviews for airlines that fly from St. Louis to Ottawa with momondo
Airline
Rating
Free Cancellation
Price
Air CanadaPriceFrom $330Free CancellationRating
7.1
10,255 reviews
Search Air Canada flights
United AirlinesPriceFrom $362Free CancellationRating
7.4
8,965 reviews
Search United Airlines flights

Traveling to a place near Ottawa?

Book flights to Ottawa if you plan to visit one of these locations
Gatineau
Smiths Falls
Calabogie
Brockville
Petawawa
Pembroke
Perth
Prescott
Winchester
Wakefield

Why use momondo?

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

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to Ottawa. Millions of users trust and use momondo every year so you are in good hands.

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

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

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

momondo provides multiple filters to help you find the best flight to Ottawa from St. Louis. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

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

Yes momondo offers price alerts on flights to Ottawa from St. Louis. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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