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Cheap flights from Portland, Maine to St. Louis from $150

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Portland, Maine to St. Louis departing on 3/31. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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0 bags

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Find the cheapest flights from Portland, Maine to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
United Airlines Logo
4:28 pm - 9:13 pm
PWM
-
STL
5h 45m
1 stop
United Airlines Logo
8:21 am - 2:20 pm
STL
-
PWM
4h 59m
1 stop
$337United Airlines
Tue, Apr 7 - Wed, Apr 8
American Airlines Logo
6:01 pm - 11:46 pm
PWM
-
STL
6h 45m
1 stop
American Airlines Logo
6:29 am - 2:37 pm
STL
-
PWM
7h 08m
1 stop
$342American Airlines
Thu, Apr 9 - Tue, Apr 14
American Airlines Logo
6:01 pm - 10:17 pm
PWM
-
STL
5h 16m
1 stop
American Airlines Logo
3:24 pm - 10:13 pm
STL
-
PWM
5h 49m
1 stop
$343American Airlines
Thu, Apr 9 - Tue, Apr 14
Delta Logo
11:45 am - 4:31 pm
PWM
-
STL
5h 46m
1 stop
Delta Logo
4:21 pm - 11:22 pm
STL
-
PWM
6h 01m
1 stop
$347Delta
Thu, Mar 26 - Mon, Mar 30
Southwest Logo
2:50 pm - 11:05 pm
PWM
-
STL
9h 15m
1 stop
Southwest Logo
4:45 pm - 12:05 am
STL
-
PWM
6h 20m
1 stop
$352Southwest
Thu, Mar 26 - Mon, Mar 30
American Airlines Logo
7:07 am - 11:45 am
PWM
-
STL
5h 38m
1 stop
American Airlines Logo
6:29 am - 2:37 pm
STL
-
PWM
7h 08m
1 stop
$353American Airlines
Wed, Apr 15 - Mon, Apr 20
Southwest Logo
2:50 pm - 11:05 pm
PWM
-
STL
9h 15m
1 stop
Southwest Logo
4:25 pm - 12:05 am
STL
-
PWM
6h 40m
2 stops
$358Southwest
Thu, Mar 26 - Mon, Mar 30
American Airlines Logo
6:00 am - 12:48 pm
PWM
-
STL
7h 48m
1 stop
American Airlines Logo
4:30 pm - 11:27 pm
STL
-
PWM
5h 57m
1 stop
$372American Airlines
Wed, Apr 8 - Sun, Apr 12
Delta Logo
6:02 am - 12:23 pm
PWM
-
STL
7h 21m
1 stop
Delta Logo
7:15 am - 1:10 pm
STL
-
PWM
4h 55m
1 stop
$377Delta
Thu, May 7 - Sun, May 10
Southwest Logo
2:50 pm - 10:55 pm
PWM
-
STL
9h 05m
2 stops
Southwest Logo
4:00 pm - 11:25 pm
STL
-
PWM
6h 25m
1 stop
$378Southwest
Thu, May 7 - Mon, May 11

American Airlines flights from Portland, Maine to St. Louis

Our best American Airlines deals on Portland, Maine to St. Louis flight tickets
American Airlines
Apr 9
PWM6:01 pmPortland
6h 45m
1 stop
STL11:46 pmLambert-St Louis
Apr 14
STL6:29 amLambert-St Louis
7h 08m
1 stop
PWM2:37 pmPortland
$342
American Airlines
Apr 9
PWM6:01 pmPortland
5h 16m
1 stop
STL10:17 pmLambert-St Louis
Apr 14
STL3:24 pmLambert-St Louis
5h 49m
1 stop
PWM10:13 pmPortland
$343
American Airlines
Apr 15
PWM7:07 amPortland
5h 38m
1 stop
STL11:45 amLambert-St Louis
Apr 20
STL6:29 amLambert-St Louis
7h 08m
1 stop
PWM2:37 pmPortland
$353

Delta flights from Portland, Maine to St. Louis

Our best Delta deals on Portland, Maine to St. Louis flight tickets
Delta
Mar 26
PWM11:45 amPortland
5h 46m
1 stop
STL4:31 pmLambert-St Louis
Mar 30
STL4:21 pmLambert-St Louis
6h 01m
1 stop
PWM11:22 pmPortland
$347
Delta
May 7
PWM6:02 amPortland
7h 21m
1 stop
STL12:23 pmLambert-St Louis
May 10
STL7:15 amLambert-St Louis
4h 55m
1 stop
PWM1:10 pmPortland
$377
Delta
May 7
PWM6:02 amPortland
7h 21m
1 stop
STL12:23 pmLambert-St Louis
May 10
STL6:00 amLambert-St Louis
5h 38m
1 stop
PWM12:38 pmPortland
$397

momondo Fare Finder

 
Customize your flight search to find flights from Portland, Maine 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 March 4, 2026.
Use the filters below to find and compare flights from Portland, Maine to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Tue 4/7

4:28 pm-9:13 pm

1 stop5h 45m

Lambert-St Louis

Wed 4/8

8:21 am-2:20 pm

1 stop4h 59m

$337

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 4/9

6:01 pm-11:46 pm

1 stop6h 45m

Lambert-St Louis

Tue 4/14

6:29 am-2:37 pm

1 stop7h 08m

$342

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 4/9

6:01 pm-10:17 pm

1 stop5h 16m

Lambert-St Louis

Tue 4/14

3:24 pm-10:13 pm

1 stop5h 49m

$343

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 3/26

11:45 am-4:31 pm

1 stop5h 46m

Lambert-St Louis

Mon 3/30

4:21 pm-11:22 pm

1 stop6h 01m

$347

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 3/26

2:50 pm-11:05 pm

1 stop9h 15m

Lambert-St Louis

Mon 3/30

4:45 pm-12:05 am

1 stop6h 20m

$352

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/15

7:07 am-11:45 am

1 stop5h 38m

Lambert-St Louis

Mon 4/20

6:29 am-2:37 pm

1 stop7h 08m

$353

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 3/26

2:50 pm-11:05 pm

1 stop9h 15m

Lambert-St Louis

Mon 3/30

4:25 pm-12:05 am

2 stops6h 40m

$358

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/8

6:00 am-12:48 pm

1 stop7h 48m

Lambert-St Louis

Sun 4/12

4:30 pm-11:27 pm

1 stop5h 57m

$372

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 5/7

6:02 am-12:23 pm

1 stop7h 21m

Lambert-St Louis

Sun 5/10

7:15 am-1:10 pm

1 stop4h 55m

$377

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 5/7

2:50 pm-10:55 pm

2 stops9h 05m

Lambert-St Louis

Mon 5/11

4:00 pm-11:25 pm

1 stop6h 25m

$378

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Portland, Maine 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 cheapest month to fly to St. Louis?

In general, September is the cheapest month to fly from Portland, Maine to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $333. The month of March is another great option to travel to St. Louis, with average flight prices from Portland, Maine averaging around $334.

What is the cheapest day to depart on your flight to St. Louis?

The cheapest day to depart on your flight to St. Louis is on a Wednesday when prices can be found for as low as $421. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $486. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

What is the cheapest time of day to depart on your flight to St. Louis?

Flying to St. Louis from Portland, Maine in the evening is the least expensive time of day to depart. momondo users have found prices as low as $424 when looking at flights departing in the evening. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $468 per ticket.

How have Portland, Maine to St. Louis flight prices changed over time?

As of March 2026, prices for Portland, Maine to St. Louis flights are approximately 13% more expensive when compared to flights at the same time last year.

When to book flights from Portland, Maine to St. Louis

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

Cheap Portland, Maine to St. Louis (PWM to STL) flight deals and tips

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

Fastest flight time

4h 54m

Direct flights

None
The fastest flight from Portland, Maine to St. Louis takes 4h 54m
There are no direct flights from Portland, Maine to St. Louis. There are no popular flight routes from Portland, Maine to St. Louis.
Search flight deals

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

    The distance between Portland and Lambert-St Louis is about 1090.4 mi. 4h 54m is a normal flight duration for this route.

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

    Prices for flights from Portland Airport to Lambert-St Louis Airport refresh daily.

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

  • How old do you have to be to fly from Portland 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 Portland 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 Portland, Maine to St. Louis?

Best airlines flying from Portland, Maine to St. Louis

Compare and see reviews for airlines that fly from Portland, Maine to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
DeltaPriceFrom $236Free CancellationRating
7.9
8,245 reviews
Search Delta flights
American AirlinesPriceFrom $296Free CancellationRating
7.1
11,379 reviews
Search American Airlines 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
Florissant
Maryland Heights
O'Fallon
St. Peters
Wentzville
Collinsville
Alton
Fenton
Farmington
Edwardsville
Festus
Clayton
Eureka
Litchfield
Glencoe
Grafton

Why use momondo?

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

Finding the right flight to St. Louis from Portland 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 Portland to St. Louis with flexible booking policies on momondo?

Flights from Portland to St. Louis with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

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

momondo helps you find the best flight between Portland and St. Louis by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

I’m not ready to book a flight from Portland 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 Portland and alert you when they change.

An easier way to manage your St. Louis trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
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