What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?

Flying on Frontier is currently your cheapest option to St. Louis, with prices starting at $198. Additional round-trip tickets that might be worth considering are offered by American Airlines and Delta, with the lowest prices starting at $272 and $290, respectively. Frontier is 53% cheaper than the average price of flights available within the next 90 days to this destination.

What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?

For one-way options, check prices for Frontier. According to our data, you can fly for as low as $100. Users have also found prices from $194 and $269 on Delta and United Airlines, respectively.

What is the cheapest day to fly from Portland, Maine to St. Louis?

Travelers seeking maximum savings on their Portland, Maine to St. Louis flight should consider departing on Thursday afternoons when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

What are the most popular airlines that fly from Portland, Maine to St. Louis?

When booking a flight from Portland, Maine to St. Louis, you may want to consider flying on American Airlines, Delta or United Airlines as they are the most popular for this route.

What is the cheapest day to fly round-trip from Portland, Maine to St. Louis?

Departing on a Monday is a good option for securing a great price. You can expect to save up to 43% when planning your travel around this day of the week.

How far in advance should I book a flight from Portland, Maine to St. Louis?

To save up to 145% on this flight, we recommend booking at least 11 days prior to travel. The price may fluctuate and will likely increase closer to your departure date. Users on Cheapflights have found tickets from Portland, Maine to St. Louis from $228 1-2 weeks out and tickets from $639 for flights departing within the next 72 hours.

What is the cheapest month to fly from Portland, Maine to St. Louis?

Due to multiple factors, expect to potentially pay more when booking in December. For low rates, February can be a great choice for travel to St. Louis. Flights to St. Louis from Portland, Maine in February are about $427 on average during February, but can be found for as low as $213.

Most accurate provider : When it comes to deals on Portland, Maine-St. Louis flights, users find the pricing of Mytrip to be most consistent on Cheapflights vs. Mytrip Users can find the same prices on Portland, Maine-St. Louis flight deals on Cheapflights vs. Mytrip >95% of the time. Price accuracy is based on data collected from Portland, Maine-St. Louis flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Portland, Maine-St. Louis flights, Cheapflights users trust Mytrip the most. Mytrip has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Portland, Maine-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Can I find deals for flights from Portland to St. Louis that include hotel bookings?

Yes. In addition to deals on Portland to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Portland to St. Louis?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Portland to St. Louis.

Can I find deals for business class flights from Portland to St. Louis?

Yes. Cheapflights offers flight deals from Portland to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$100+ Flights from Portland, ME to St. Louis

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

Find cheap flights from Portland to St. Louis with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Portland to Lambert-St Louis are usually found in February or January, booked 10 days in advance, depart on a Tuesday or Friday and return on a Tuesday

Cheap flight deals from Portland to St. Louis

Most accurate provider	Mytrip 3 stars
Most trusted provider	Mytrip 3 stars
Round-trip from	$198 (Booking.com)
One-way from	$100 (Booking.com)
Popular in	December
Cheapest in	February
Average price	$526

Provider with most accurate pricing for Portland-Lambert-St Louis flight deals.

Search Deals

Provider most trusted by Cheapflights users for Portland-Lambert-St Louis flights.

Search Deals

From Portland to Lambert-St Louis

Search Deals

One-way flight from Portland to Lambert-St Louis

Search Deals

Highest demand for flights based on searches. 4% potential increase in price ($17 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($11 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in April 2025

Search Deals

Find flight deals from Portland to St. Louis

Cheapest flights from Portland to St. Louis
Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 24, 2025.

Mon 5/59:30 pmPWM - STL

1 stop27h 36mFrontier

Wed 5/75:45 pmSTL - PWM

1 stop25h 44mFrontier

Deal found 4/23

$198

Wed 5/2812:08 pmPWM - STL

1 stop12h 43mAmerican Airlines

Wed 6/41:59 pmSTL - PWM

1 stop8h 06mAmerican Airlines

Deal found 4/23

$272

Wed 5/216:05 amPWM - STL

2 stops9h 30mDelta

Wed 5/285:40 pmSTL - PWM

1 stop5h 19mDelta

Deal found 4/23

$290

Mon 7/285:40 amPWM - STL

2 stops8h 20mSouthwest

Mon 8/44:35 pmSTL - PWM

2 stops6h 30mSouthwest

Deal found 4/23

$413

Fri 6/134:43 pmPWM - STL

1 stop7h 02mUnited Airlines

Mon 6/166:30 amSTL - PWM

2 stops7h 23mUnited Airlines

Deal found 4/23

$414

Sun 5/183:17 pmPWM - STL

3 stops28h 24mMultiple Airlines

Thu 5/2210:10 amSTL - PWM

2 stops32h 27mMultiple Airlines

Deal found 4/23

$635

Best flights from Portland to St. Louis
Discover carefully curated flight deals from Portland to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated April 24, 2025.

Mon 5/59:30 pmPWM - STL

1 stop27h 36mFrontier

Wed 5/75:45 pmSTL - PWM

1 stop25h 44mFrontier

Deal found 4/23

$198

Wed 5/2812:08 pmPWM - STL

1 stop12h 43mAmerican Airlines

Wed 6/41:59 pmSTL - PWM

1 stop8h 06mAmerican Airlines

Deal found 4/23

$272

Wed 5/216:05 amPWM - STL

2 stops9h 30mDelta

Wed 5/285:40 pmSTL - PWM

1 stop5h 19mDelta

Deal found 4/23

$290

Mon 7/285:40 amPWM - STL

2 stops8h 20mSouthwest

Mon 8/44:35 pmSTL - PWM

2 stops6h 30mSouthwest

Deal found 4/23

$413

Fri 6/134:43 pmPWM - STL

1 stop7h 02mUnited Airlines

Mon 6/166:30 amSTL - PWM

2 stops7h 23mUnited Airlines

Deal found 4/23

$414

Sun 5/183:17 pmPWM - STL

3 stops28h 24mMultiple Airlines

Thu 5/2210:10 amSTL - PWM

2 stops32h 27mMultiple Airlines

Deal found 4/23

$635

Last-minute flights from Portland to St. Louis
Discover last-minute flight deals from Portland to St. Louis. Data last updated April 24, 2025 and is based on user searches.

Tue 4/297:20 amPWM - STL

1 stop8h 25mAmerican Airlines

Fri 5/95:12 amSTL - PWM

1 stop6h 27mAmerican Airlines

Deal found 4/23

$530

Tue 4/297:00 amPWM - STL

2 stops10h 52mDelta

Fri 5/96:00 amSTL - PWM

1 stop5h 57mDelta

Deal found 4/23

$600

Fri 5/26:13 amPWM - STL

1 stop5h 50mUnited Airlines

Sun 5/46:30 amSTL - PWM

1 stop7h 08mUnited Airlines

Deal found 4/22

$747

Mon 5/59:30 pmPWM - STL

1 stop27h 36mFrontier

Wed 5/75:45 pmSTL - PWM

1 stop25h 44mFrontier

Deal found 4/23

$198

Thu 5/86:00 amPWM - STL

2 stops9h 47mUnited Airlines

Mon 5/123:43 pmSTL - PWM

1 stop4h 33mUnited Airlines

Deal found 4/23

$452

Tue 5/132:20 pmPWM - STL

2 stops6h 40mSouthwest

Fri 5/166:00 pmSTL - PWM

1 stop4h 20mSouthwest

Deal found 4/23

$462

Sun 5/183:17 pmPWM - STL

3 stops28h 24mMultiple Airlines

Thu 5/2210:10 amSTL - PWM

2 stops32h 27mMultiple Airlines

Deal found 4/23

$635

Wed 5/216:05 amPWM - STL

2 stops9h 30mDelta

Wed 5/285:40 pmSTL - PWM

1 stop5h 19mDelta

Deal found 4/23

$290

Wed 5/2812:08 pmPWM - STL

1 stop12h 43mAmerican Airlines

Wed 6/41:59 pmSTL - PWM

1 stop8h 06mAmerican Airlines

Deal found 4/23

$272

One-way flights from Portland to St. Louis
Search for one-way flight options from Portland to St. Louis. Find affordable one-way fares based on user searches. Data last updated April 24, 2025.

Sat 5/107:30 pmPWM - STL

1 stop29h 36mFrontier

Deal found 4/23

$100

Sun 6/297:02 pmPWM - STL

1 stop5h 49mDelta

Deal found 4/22

$194

Sat 7/266:20 pmPWM - STL

1 stop5h 25mUnited Airlines

Deal found 4/23

$269

Cheapflights Fare Finder

Use the filters below to find and compare flights from Portland to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 5/5

9:30 pm-12:06 am

1 stop27h 36m

Lambert-St Louis

Wed 5/7

5:45 pm-8:29 pm

1 stop25h 44m

$198

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/28

12:08 pm-11:51 pm

1 stop12h 43m

Lambert-St Louis

Wed 6/4

1:59 pm-11:05 pm

1 stop8h 06m

$272

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/21

6:05 am-2:35 pm

2 stops9h 30m

Lambert-St Louis

Wed 5/28

5:40 pm-11:59 pm

1 stop5h 19m

$290

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Mon 7/28

5:40 am-1:00 pm

2 stops8h 20m

Lambert-St Louis

Mon 8/4

4:35 pm-12:05 am

2 stops6h 30m

$413

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Fri 6/13

4:43 pm-10:45 pm

1 stop7h 02m

Lambert-St Louis

Mon 6/16

6:30 am-2:53 pm

2 stops7h 23m

$414

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 5/18

3:17 pm-6:41 pm

3 stops28h 24m

Lambert-St Louis

Thu 5/22

10:10 am-7:37 pm

2 stops32h 27m

$635

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 5/10

7:30 pm-12:06 am

1 stop29h 36m

$100

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 6/29

7:02 pm-11:51 pm

1 stop5h 49m

$194

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 7/26

6:20 pm-10:45 pm

1 stop5h 25m

$269

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/23

Compare providers for flights from Portland to St. Louis

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Portland to St. Louis in April.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy1 star	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*2 stars
eDreams	Price Accuracy3 stars	Trust Score*3 stars
Gotogate	Price Accuracy3 stars	Trust Score*2 stars
Mytrip	Price Accuracy3 stars	Trust Score*3 stars
Flightnetwork	Price Accuracy2 stars	Trust Score*3 stars
Cheapfaremart	Price Accuracy-	Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Portland, Maine-St. Louis flights, users find the pricing of Mytrip to be most consistent on Cheapflights vs. Mytrip Users can find the same prices on Portland, Maine-St. Louis flight deals on Cheapflights vs. Mytrip >95% of the time. Price accuracy is based on data collected from Portland, Maine-St. Louis flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Portland, Maine-St. Louis flights, Cheapflights users trust Mytrip the most. Mytrip has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Portland, Maine-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Portland to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Portland with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Portland to St. Louis

How far ahead should I book a flight from Portland, Maine to St. Louis?

The price you pay for your flight from Portland, Maine to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 10 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

Currently, August is the cheapest month in which you can book a flight from Portland, Maine to St. Louis (average of $311). Flying from Portland, Maine to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from PWM to STL?

When flying from Portland, Maine to St. Louis, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 28% versus a flight at noon.

Rainfall in St. Louis by month

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

Reviews of airlines servicing St. Louis

Peruse reviews from past customers who have flown with Southwest, Delta and United Airlines from Portland to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

Southwest

8.0

Very good

4,286 reviews

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

Delta

8.0

Very good

7,920 reviews

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

United Airlines

7.4

Good

8,685 reviews

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

American Airlines

7.2

Good

10,000 reviews

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

Frontier

6.0

Okay

3,283 reviews

Southwest

8.0

Very good

4,286 reviews

Reviews

1 / 20

10.0

Excellent

Gina,Apr 2025

LAS - DEN

Good, the crew was friendly and helpful. The pilot had great skills in keeping the plane stable through rough turbulence. Smooth landing, too! Thank you!

Related info for your journey

What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?
Flying on Frontier is currently your cheapest option to St. Louis, with prices starting at $198. Additional round-trip tickets that might be worth considering are offered by American Airlines and Delta, with the lowest prices starting at $272 and $290, respectively. Frontier is 53% cheaper than the average price of flights available within the next 90 days to this destination.
What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?
For one-way options, check prices for Frontier. According to our data, you can fly for as low as $100. Users have also found prices from $194 and $269 on Delta and United Airlines, respectively.
Can I find deals for flights from Portland to St. Louis that include hotel bookings?
Yes. In addition to deals on Portland to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Portland to St. Louis?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Portland to St. Louis.
Can I find deals for business class flights from Portland to St. Louis?
Yes. Cheapflights offers flight deals from Portland to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Portland, Maine to St. Louis?
Currently, August is the cheapest month in which you can book a flight from Portland, Maine to St. Louis (average of $311). Flying from Portland, Maine to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Fenton

Maryland Heights

Fairview Heights

Collinsville

Wentzville

Eureka

St. Peters

Festus

Glencoe

Alton

Farmington

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Portland to St. Louis

Boston to Kansas City flights

Boston to St. Louis flights

Boston to Springfield flights

Portland to Kansas City flights

Portland to Springfield flights

Bangor to St. Louis flights

Bangor to Kansas City flights

Boston to Columbia flights

Boston to Joplin flights

Complete your trip

St. Louis car rentals

Lambert-St Louis Airport car rentals

Springfield Capital Airport car rentals

Belleville Airport car rentals

Marion Williamson County Airport car rentals

Kansas City car rentals

Springfield car rentals

Columbia car rentals

Joplin car rentals

Fort Leonard Wood car rentals

Downtown car rentals

The Hill car rentals

Other flights to St. Louis

Top 4 airlines flying from Portland to St. Louis

Airline	Cheapest	Average	Flexibility	On-time
American Airlines	Cheapest$308	Average$424	FlexibilityNo cancel fee	On-time71%
Delta	Cheapest$333	Average$455	FlexibilityNo cancel fee	On-timeN/A
United Airlines	Cheapest$341	Average$466	FlexibilityNo cancel fee	On-time69%
Southwest	Cheapest$351	Average$417	FlexibilityNo cancel fee	On-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.

$100+ Cheap flights from Portland, ME to St. Louis (PWM - STL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 5/10. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Portland to St. Louis with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheapflights Tip: The best prices from Portland to Lambert-St Louis are usually found in February or January, booked 10 days in advance, depart on a Tuesday or Friday and return on a Tuesday

Cheap flight deals from Portland to St. Louis

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Find flight deals from Portland to St. Louis

Cheapest flights from Portland to St. LouisExplore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 24, 2025.

Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 24, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Portland to St. Louis that are best for you.

Compare providers for flights from Portland to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Portland to St. Louis in April.

Best time to book a flight from Portland to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Portland with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Portland to St. Louis

How far ahead should I book a flight from Portland, Maine to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Portland to St. Louis. Price data was last updated on April 18, 2025.

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

What is the cheapest time of day to fly from PWM to STL?

Find hourly flight availability from Portland to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated April 24, 2025.

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

Reviews of airlines servicing St. Louis

Peruse reviews from past customers who have flown with Southwest, Delta and United Airlines from Portland to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Portland to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?

What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?

Can I find deals for flights from Portland to St. Louis that include hotel bookings?

How can I find direct flights from Portland to St. Louis?

Can I find deals for business class flights from Portland to St. Louis?

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

Traveling to a place near Portland?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Portland to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.

Top 4 airlines flying from Portland to St. Louis

100% Free

Book with Flexibility

Travel Smart

Cheapest flights from Portland to St. Louis
Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 24, 2025.