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.

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

American Airlines and United Airlines are the most popular carriers operating from Portland to Lambert-St Louis

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 November 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.

$244 Cheap Flights from Portland to St. Louis in 2025/26

1 adult

0 bags

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Not ready to book? to track prices.

Search flight deals

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

Round-trip

One-way

Last minute

Cheap round-trip flights

Enter your travel dates to find the best prices.

4:53 pm - 8:47 pmPWM-STL

4h 54m1 stop

6:39 am - 12:13 pmSTL-PWM

4h 34m1 stop

$318Delta

Find Deal

Wed, Dec 3 - Sat, Dec 6

6:00 am - 1:02 pmPWM-STL

8h 02m2 stops

6:39 am - 12:13 pmSTL-PWM

4h 34m1 stop

$323Delta

Find Deal

Wed, Dec 3 - Sat, Dec 6

3:15 pm - 9:40 amPWM-STL

19h 25m2 stops

4:13 pm - 9:06 amSTL-PWM

15h 53m1 stop

$350Multiple Airlines

Find Deal

Sun, Nov 16 - Thu, Nov 20

5:37 pm - 11:56 pmPWM-STL

7h 19m1 stop

8:39 am - 5:05 pmSTL-PWM

7h 26m1 stop

$382American Airlines

Find Deal

Sun, Nov 23 - Wed, Nov 26

7:10 pm - 11:50 pmPWM-STL

5h 40m1 stop

8:00 am - 3:14 pmSTL-PWM

6h 14m1 stop

$407United Airlines

Find Deal

Fri, Mar 6 - Sat, Mar 7

6:00 am - 2:31 pmPWM-STL

9h 31m2 stops

8:00 am - 3:14 pmSTL-PWM

6h 14m1 stop

$412United Airlines

Find Deal

Fri, Mar 6 - Sat, Mar 7

7:00 am - 12:27 pmPWM-STL

6h 27m1 stop

6:00 am - 11:22 amSTL-PWM

4h 22m1 stop

$433American Airlines

Find Deal

Thu, Feb 26 - Sun, Mar 1

3:15 pm - 11:50 pmPWM-STL

9h 35m1 stop

5:10 am - 11:10 amSTL-PWM

5h 00m1 stop

$442Southwest

Find Deal

Wed, Nov 26 - Fri, Nov 28

5:30 pm - 11:50 pmPWM-STL

7h 20m1 stop

5:05 am - 2:25 pmSTL-PWM

8h 20m1 stop

$502Southwest

Find Deal

Mon, Dec 22 - Sat, Jan 3

9:46 am - 10:33 pmPWM-STL

13h 47m1 stop

4:27 pm - 9:06 amSTL-PWM

15h 39m1 stop

$508Multiple Airlines

Find Deal

Mon, Dec 22 - Sun, Jan 4

Delta flights from Portland, Maine to St. Louis

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

Delta

Dec 3

PWM4:53 pmPortland

4h 54m

1 stop

STL8:47 pmLambert-St Louis

Dec 6

STL6:39 amLambert-St Louis

4h 34m

1 stop

PWM12:13 pmPortland

$318

Find similar

Delta

Dec 3

PWM6:00 amPortland

8h 02m

2 stops

STL1:02 pmLambert-St Louis

Dec 6

STL6:39 amLambert-St Louis

4h 34m

1 stop

PWM12:13 pmPortland

$323

Find similar

Delta

Dec 3

PWM6:00 amPortland

8h 02m

2 stops

STL1:02 pmLambert-St Louis

Dec 6

STL6:00 amLambert-St Louis

9h 00m

2 stops

PWM4:00 pmPortland

$328

Find similar

American Airlines flights from Portland, Maine to St. Louis

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

American Airlines

Nov 23

PWM5:37 pmPortland

7h 19m

1 stop

STL11:56 pmLambert-St Louis

Nov 26

STL8:39 amLambert-St Louis

7h 26m

1 stop

PWM5:05 pmPortland

$382

Find similar

American Airlines

Feb 26

PWM7:00 amPortland

6h 27m

1 stop

STL12:27 pmLambert-St Louis

Mar 1

STL6:00 amLambert-St Louis

4h 22m

1 stop

PWM11:22 amPortland

$433

Find similar

American Airlines

Nov 16

PWM7:02 amPortland

7h 15m

1 stop

STL1:17 pmLambert-St Louis

Nov 20

STL9:50 amLambert-St Louis

5h 50m

1 stop

PWM4:40 pmPortland

$540

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

Wed 12/3

4:53 pm-8:47 pm

1 stop4h 54m

Lambert-St Louis

Sat 12/6

6:39 am-12:13 pm

1 stop4h 34m

$318

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 12/3

6:00 am-1:02 pm

2 stops8h 02m

Lambert-St Louis

Sat 12/6

6:39 am-12:13 pm

1 stop4h 34m

$323

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 11/16

3:15 pm-9:40 am

2 stops19h 25m

Lambert-St Louis

Thu 11/20

4:13 pm-9:06 am

1 stop15h 53m

$350

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 11/23

5:37 pm-11:56 pm

1 stop7h 19m

Lambert-St Louis

Wed 11/26

8:39 am-5:05 pm

1 stop7h 26m

$382

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Fri 3/6

7:10 pm-11:50 pm

1 stop5h 40m

Lambert-St Louis

Sat 3/7

8:00 am-3:14 pm

1 stop6h 14m

$407

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Fri 3/6

6:00 am-2:31 pm

2 stops9h 31m

Lambert-St Louis

Sat 3/7

8:00 am-3:14 pm

1 stop6h 14m

$412

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 2/26

7:00 am-12:27 pm

1 stop6h 27m

Lambert-St Louis

Sun 3/1

6:00 am-11:22 am

1 stop4h 22m

$433

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 11/26

3:15 pm-11:50 pm

1 stop9h 35m

Lambert-St Louis

Fri 11/28

5:10 am-11:10 am

1 stop5h 00m

$442

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 12/22

5:30 pm-11:50 pm

1 stop7h 20m

Lambert-St Louis

Sat 1/3

5:05 am-2:25 pm

1 stop8h 20m

$502

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 12/22

9:46 am-10:33 pm

1 stop13h 47m

Lambert-St Louis

Sun 1/4

4:27 pm-9:06 am

1 stop15h 39m

$508

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 13 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 $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 November 2025, prices for Portland, Maine to St. Louis flights are approximately 33% 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 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 November 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 (67% of total bookings). The next most popular airline is Delta (33%).

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 8,001 reviews	Search Delta flights
American Airlines	PriceFrom $300	Free Cancellation	Rating 7.2 11,034 reviews	Search American Airlines flights
Southwest	PriceFrom $371	Free Cancellation	Rating 8.0 4,240 reviews	Search Southwest flights

St. Charles

Chesterfield

Hermann

Fairview Heights

Maryland Heights

Florissant

O'Fallon

Wentzville

Fenton

Collinsville

St. Peters

Alton

Farmington

Festus

Glencoe

Edwardsville

Clayton

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.