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

American Airlines, Delta, and Southwest are the most popular carriers 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 55% 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 4 as of August 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.

$144 Cheap Flights from Portland to St. Louis in 2025

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

Round-trip

One-way

Last minute

Cheap round-trip flights

6:00 am - 12:19 pmPWM-STL

7h 19m1 stop

1:26 pm - 10:00 pmSTL-PWM

7h 34m1 stop

$297Delta

Find Deal

mié., sep. 17 - sáb., sep. 20

6:00 am - 1:20 pmPWM-STL

8h 20m2 stops

1:26 pm - 10:00 pmSTL-PWM

7h 34m1 stop

$302Delta

Find Deal

mié., sep. 17 - sáb., sep. 20

6:00 am - 4:05 pmPWM-STL

11h 05m2 stops

10:40 am - 10:00 pmSTL-PWM

10h 20m2 stops

$307Delta

Find Deal

mié., sep. 17 - sáb., sep. 20

5:41 pm - 11:57 pmPWM-STL

7h 16m1 stop

3:23 pm - 9:44 pmSTL-PWM

5h 21m1 stop

$317United Airlines

Find Deal

vie., sep. 26 - lun., sep. 29

6:14 am - 10:49 amPWM-STL

5h 35m1 stop

3:23 pm - 11:59 pmSTL-PWM

7h 36m2 stops

$322United Airlines

Find Deal

vie., sep. 26 - lun., sep. 29

5:59 pm - 11:58 pmPWM-STL

6h 59m1 stop

7:16 am - 2:56 pmSTL-PWM

6h 40m1 stop

$347American Airlines

Find Deal

jue., oct. 16 - dom., oct. 19

5:42 am - 3:55 pmPWM-STL

11h 13m2 stops

4:13 pm - 12:05 amSTL-PWM

6h 52m1 stop

$348Delta

Find Deal

mié., oct. 15 - sáb., oct. 18

6:00 am - 10:21 amPWM-STL

5h 21m1 stop

6:00 am - 12:29 pmSTL-PWM

5h 29m1 stop

$357American Airlines

Find Deal

jue., sep. 18 - dom., sep. 21

4:55 pm - 10:05 pmPWM-STL

6h 10m1 stop

4:15 pm - 11:20 pmSTL-PWM

6h 05m1 stop

$447Southwest

Find Deal

mar., sep. 9 - vie., sep. 12

5:50 am - 1:10 pmPWM-STL

8h 20m2 stops

2:45 pm - 11:20 pmSTL-PWM

7h 35m2 stops

$483Southwest

Find Deal

mar., sep. 9 - vie., sep. 12

Delta flights from Portland, Maine to St. Louis

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

Delta

Sep 17

PWM6:00 amPortland

7h 19m

1 stop

STL12:19 pmLambert-St Louis

Sep 20

STL1:26 pmLambert-St Louis

7h 34m

1 stop

PWM10:00 pmPortland

$297

Find similar

Delta

Sep 17

PWM6:00 amPortland

8h 20m

2 stops

STL1:20 pmLambert-St Louis

Sep 20

STL1:26 pmLambert-St Louis

7h 34m

1 stop

PWM10:00 pmPortland

$302

Find similar

Delta

Sep 17

PWM6:00 amPortland

11h 05m

2 stops

STL4:05 pmLambert-St Louis

Sep 20

STL10:40 amLambert-St Louis

10h 20m

2 stops

PWM10:00 pmPortland

$307

Find similar

United Airlines flights from Portland, Maine to St. Louis

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

United Airlines

Sep 26

PWM5:41 pmPortland

7h 16m

1 stop

STL11:57 pmLambert-St Louis

Sep 29

STL3:23 pmLambert-St Louis

5h 21m

1 stop

PWM9:44 pmPortland

$317

Find similar

United Airlines

Sep 26

PWM6:14 amPortland

5h 35m

1 stop

STL10:49 amLambert-St Louis

Sep 29

STL3:23 pmLambert-St Louis

7h 36m

2 stops

PWM11:59 pmPortland

$322

Find similar

United Airlines

Sep 3

PWM6:00 amPortland

9h 19m

2 stops

STL2:19 pmLambert-St Louis

Sep 6

STL6:35 amLambert-St Louis

6h 50m

2 stops

PWM2:25 pmPortland

$327

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

mié. 9/17

6:00 am-12:19 pm

1 stop7h 19m

Lambert-St Louis

sáb. 9/20

1:26 pm-10:00 pm

1 stop7h 34m

$297

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

mié. 9/17

6:00 am-1:20 pm

2 stops8h 20m

Lambert-St Louis

sáb. 9/20

1:26 pm-10:00 pm

1 stop7h 34m

$302

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

mié. 9/17

6:00 am-4:05 pm

2 stops11h 05m

Lambert-St Louis

sáb. 9/20

10:40 am-10:00 pm

2 stops10h 20m

$307

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

vie. 9/26

5:41 pm-11:57 pm

1 stop7h 16m

Lambert-St Louis

lun. 9/29

3:23 pm-9:44 pm

1 stop5h 21m

$317

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

vie. 9/26

6:14 am-10:49 am

1 stop5h 35m

Lambert-St Louis

lun. 9/29

3:23 pm-11:59 pm

2 stops7h 36m

$322

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

jue. 10/16

5:59 pm-11:58 pm

1 stop6h 59m

Lambert-St Louis

dom. 10/19

7:16 am-2:56 pm

1 stop6h 40m

$347

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

mié. 10/15

5:42 am-3:55 pm

2 stops11h 13m

Lambert-St Louis

sáb. 10/18

4:13 pm-12:05 am

1 stop6h 52m

$348

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

jue. 9/18

6:00 am-10:21 am

1 stop5h 21m

Lambert-St Louis

dom. 9/21

6:00 am-12:29 pm

1 stop5h 29m

$357

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

mar. 9/9

4:55 pm-10:05 pm

1 stop6h 10m

Lambert-St Louis

vie. 9/12

4:15 pm-11:20 pm

1 stop6h 05m

$447

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

mar. 9/9

5:50 am-1:10 pm

2 stops8h 20m

Lambert-St Louis

vie. 9/12

2:45 pm-11:20 pm

2 stops7h 35m

$483

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 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 $250. The month of September is another great option to travel to St. Louis, with average flight prices from Portland, Maine averaging around $340.

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 August 2025, prices for Portland, Maine to St. Louis flights are approximately 27% 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

Direct flights	None

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 53m 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 4 as of August 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 (58% of total bookings). The next most popular airlines are Delta (22%), Southwest (11%), and United Airlines (9%).

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 7,977 reviews	Search Delta flights
American Airlines	PriceFrom $300	Free Cancellation	Rating 7.2 10,000 reviews	Search American Airlines flights
United Airlines	PriceFrom $341	Free Cancellation	Rating 7.4 8,945 reviews	Search United Airlines flights
Southwest	PriceFrom $351	Free Cancellation	Rating 8.0 4,241 reviews	Search Southwest flights

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Chesterfield

Hermann

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Maryland Heights

Florissant

O'Fallon

Fenton

Collinsville

Wentzville

Alton

St. Peters

Farmington

Festus

Glencoe

Clayton

Edwardsville

Eureka

Litchfield

Shrewsbury

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.