What is the cheapest airline that flies from Portland to Lambert-St Louis?

Delta is the most popular carrier operating from Portland to Lambert-St Louis

What airlines fly to St. Louis?

American Airlines, Southwest and Delta are the top three most popular airlines that fly to St. Louis from Portland, Maine according to our data. American Airlines is the first choice among our users, with 54% of people opting to fly with this airline when traveling to St. Louis. Keep in mind that there are 6 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

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?

The number of operators available for flights from Portland Airport to Lambert-St Louis Airport is 2 as of December 2025.

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.

$257 Cheap Flights from Portland to St. Louis in 2025/26

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

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Cheap round-trip flights

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9:47 am - 11:33 pm

PWM

STL

14h 46m1 stop

5:42 pm - 10:22 am

STL

PWM

15h 40m1 stop

$310Multiple Airlines

Mon, Jan 26 - Tue, Jan 27

7:27 pm - 11:59 pm

PWM

STL

5h 32m1 stop

8:30 am - 2:31 pm

STL

PWM

5h 01m1 stop

$317United Airlines

Mon, Jan 26 - Wed, Jan 28

11:29 am - 11:33 pm

PWM

STL

13h 04m2 stops

5:42 pm - 10:22 am

STL

PWM

15h 40m1 stop

$320Multiple Airlines

Mon, Jan 26 - Tue, Jan 27

6:00 am - 2:49 pm

PWM

STL

9h 49m2 stops

9:45 am - 5:16 pm

STL

PWM

6h 31m1 stop

$322Delta

Mon, Jan 26 - Wed, Jan 28

3:12 pm - 10:58 pm

PWM

STL

8h 46m2 stops

6:30 am - 2:31 pm

STL

PWM

7h 01m2 stops

$327United Airlines

Mon, Jan 26 - Tue, Jan 27

4:10 pm - 9:13 pm

PWM

STL

6h 03m1 stop

7:00 am - 1:56 pm

STL

PWM

5h 56m1 stop

$361United Airlines

Sat, Jan 17 - Tue, Jan 20

4:10 pm - 9:13 pm

PWM

STL

6h 03m1 stop

6:30 am - 2:31 pm

STL

PWM

7h 01m2 stops

$366United Airlines

Sat, Jan 17 - Tue, Jan 20

6:00 am - 5:43 pm

PWM

STL

12h 43m2 stops

11:20 am - 11:27 pm

STL

PWM

11h 07m2 stops

$371United Airlines

Sat, Jan 17 - Tue, Jan 20

8:40 am - 9:13 pm

PWM

STL

13h 33m2 stops

11:20 am - 11:27 pm

STL

PWM

11h 07m2 stops

$398United Airlines

Sat, Jan 17 - Tue, Jan 20

11:53 am - 5:21 pm

PWM

STL

6h 28m1 stop

5:29 am - 1:27 pm

STL

PWM

6h 58m1 stop

$407American Airlines

Wed, Apr 15 - Mon, Apr 20

United Airlines flights from Portland, Maine to St. Louis

Our best United Airlines deals on Portland, Maine to St. Louis flight tickets

United Airlines

Jan 26

PWM7:27 pmPortland

5h 32m

1 stop

STL11:59 pmLambert-St Louis

Jan 28

STL8:30 amLambert-St Louis

5h 01m

1 stop

PWM2:31 pmPortland

$317

Find similar

United Airlines

Jan 26

PWM3:12 pmPortland

8h 46m

2 stops

STL10:58 pmLambert-St Louis

Jan 27

STL6:30 amLambert-St Louis

7h 01m

2 stops

PWM2:31 pmPortland

$327

Find similar

United Airlines

Jan 17

PWM4:10 pmPortland

6h 03m

1 stop

STL9:13 pmLambert-St Louis

Jan 20

STL7:00 amLambert-St Louis

5h 56m

1 stop

PWM1:56 pmPortland

$361

Find similar

Delta flights from Portland, Maine to St. Louis

Our best Delta deals on Portland, Maine to St. Louis flight tickets

Delta

Jan 26

PWM6:00 amPortland

9h 49m

2 stops

STL2:49 pmLambert-St Louis

Jan 28

STL9:45 amLambert-St Louis

6h 31m

1 stop

PWM5:16 pmPortland

$322

Find similar

Delta

May 1

PWM4:45 pmPortland

7h 27m

2 stops

STL11:12 pmLambert-St Louis

May 6

STL6:10 amLambert-St Louis

8h 48m

2 stops

PWM3:58 pmPortland

$427

Find similar

Delta

Mar 14

PWM4:48 pmPortland

4h 54m

1 stop

STL8:42 pmLambert-St Louis

Mar 22

STL6:32 amLambert-St Louis

4h 37m

1 stop

PWM12:09 pmPortland

$473

Find similar

momondo Fare Finder

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

Mon 1/26

9:47 am-11:33 pm

1 stop14h 46m

Lambert-St Louis

Tue 1/27

5:42 pm-10:22 am

1 stop15h 40m

$310

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 1/26

7:27 pm-11:59 pm

1 stop5h 32m

Lambert-St Louis

Wed 1/28

8:30 am-2:31 pm

1 stop5h 01m

$317

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 1/26

11:29 am-11:33 pm

2 stops13h 04m

Lambert-St Louis

Tue 1/27

5:42 pm-10:22 am

1 stop15h 40m

$320

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 1/26

6:00 am-2:49 pm

2 stops9h 49m

Lambert-St Louis

Wed 1/28

9:45 am-5:16 pm

1 stop6h 31m

$322

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 1/26

3:12 pm-10:58 pm

2 stops8h 46m

Lambert-St Louis

Tue 1/27

6:30 am-2:31 pm

2 stops7h 01m

$327

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 1/17

4:10 pm-9:13 pm

1 stop6h 03m

Lambert-St Louis

Tue 1/20

7:00 am-1:56 pm

1 stop5h 56m

$361

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 1/17

4:10 pm-9:13 pm

1 stop6h 03m

Lambert-St Louis

Tue 1/20

6:30 am-2:31 pm

2 stops7h 01m

$366

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 1/17

6:00 am-5:43 pm

2 stops12h 43m

Lambert-St Louis

Tue 1/20

11:20 am-11:27 pm

2 stops11h 07m

$371

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 1/17

8:40 am-9:13 pm

2 stops13h 33m

Lambert-St Louis

Tue 1/20

11:20 am-11:27 pm

2 stops11h 07m

$398

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/15

11:53 am-5:21 pm

1 stop6h 28m

Lambert-St Louis

Mon 4/20

5:29 am-1:27 pm

1 stop6h 58m

$407

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 17 resultsSorted by cheapest first

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

Prices

Airlines

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

In general, February 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 $269. The month of September is another great option to travel to St. Louis, with average flight prices from Portland, Maine averaging around $333.

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 Tuesday when prices can be found for as low as $443. 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 Monday because tickets tend to average around $638. 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 afternoon is the least expensive time of day to depart. momondo users have found prices as low as $441 when looking at flights departing in the afternoon. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $609 per ticket.

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

As of December 2025, 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?
The number of operators available for flights from Portland Airport to Lambert-St Louis Airport is 2 as of December 2025.
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?
Based on momondo bookings for this flight route, the most popular airline on flight routes from Portland, Maine to St. Louis is American Airlines (68% of total bookings). The next most popular airline is Delta (32%).

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
Delta	PriceFrom $236	Free Cancellation	Rating 7.9 8,013 reviews		Search Delta flights
American Airlines	PriceFrom $300	Free Cancellation	Rating 7.2 11,062 reviews		Search American Airlines flights

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O'Fallon

Florissant

Fenton

St. Peters

Wentzville

Collinsville

Alton

Farmington

Clayton

Festus

Glencoe

Eureka

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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.