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$514+ Cheap flights from Portland, ME (PWM) to London (LON)

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 12/21. Fares are subject to change and may not be available on all flights or dates of travel.
PWM — LON
Nov 22 — Nov 291
Sat 11/22
Sat 11/29
1 adult, Economy
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Find flight deals from Portland to London

Cheapest flights from Portland to London
Explore the most affordable flight options available from Portland to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 23, 2025.

This Delta deal was found by Cheapflights users on 10/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/182:30 pmPWM - LHR
1 stop11h 25mDelta
Tue 11/256:30 amLHR - PWM
2 stops20h 49mDelta
Deal found 10/22$594
This KLM deal was found by Cheapflights users on 10/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/184:53 pmPWM - LHR
1 stop10h 52mKLM
Tue 11/2510:45 amLHR - PWM
1 stop16h 34mKLM
Deal found 10/22$600
This Justfly.com deal was found by Cheapflights users on 10/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/279:00 amPWM - LHR
2 stops28h 30mScandinavian Airlines
Wed 12/36:40 amLHR - PWM
2 stops22h 19mScandinavian Airlines
Deal found 10/23$637
This Air France deal was found by Cheapflights users on 10/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/74:53 pmPWM - LHR
1 stop10h 52mAir France
Sun 12/148:55 amLHR - PWM
1 stop18h 28mAir France
Deal found 10/22$642
This Delta deal was found by Cheapflights users on 10/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/276:00 amPWM - LHR
1 stop19h 25mDelta
Thu 12/46:20 amLHR - PWM
2 stops22h 39mDelta
Deal found 10/21$643
This Delta deal was found by Cheapflights users on 10/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/276:00 amPWM - LHR
1 stop19h 25mDelta
Fri 12/511:45 amLHR - PWM
2 stops17h 14mDelta
Deal found 10/21$644
This Scandinavian Airlines deal was found by Cheapflights users on 10/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Scandinavian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/279:00 amPWM - LHR
2 stops27h 40mScandinavian Airlines
Thu 12/46:40 amLHR - PWM
2 stops22h 19mScandinavian Airlines
Deal found 10/21$645
This Delta deal was found by Cheapflights users on 10/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/74:53 pmPWM - LHR
1 stop10h 52mDelta
Sun 12/148:40 amLHR - PWM
2 stops36h 27mDelta
Deal found 10/23$649
This Kiwi.com deal was found by Cheapflights users on 10/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/273:15 pmPWM - LGW
2 stops37h 45mMultiple Airlines
Fri 12/52:00 pmLGW - PWM
1 stop25h 36mMultiple Airlines
Deal found 10/23$680
This Kiwi.com deal was found by Cheapflights users on 10/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/273:15 pmPWM - LGW
2 stops37h 45mMultiple Airlines
Thu 12/42:00 pmLGW - PWM
1 stop24h 06mMultiple Airlines
Deal found 10/23$730
This United Airlines deal was found by Cheapflights users on 10/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/279:54 amPWM - LCY
2 stops22h 01mMultiple Airlines
Tue 12/26:15 pmLCY - PWM
2 stops29h 28mMultiple Airlines
Deal found 10/21$735
This KLM deal was found by Cheapflights users on 10/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/42:34 pmPWM - LCY
2 stops13h 16mKLM
Mon 12/810:00 amLCY - PWM
2 stops17h 23mKLM
Deal found 10/22$750

Cheap flight deals from Portland to London

Discover tips and strategies to find the most affordable flight options for your journey from Portland (PWM) to London (LON). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated October 23, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$594
(Delta)

One-way from

$514
(Mytrip)

Popular in

June

Cheapest in

October

Average price

$638
Provider with most accurate pricing for Portland-London (LON) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Portland-London (LON) flights.
Search Deals
From Portland to London (LON)
Search Deals
One-way flight from Portland to London (LON)
Search Deals
Highest demand for flights based on searches. 16% potential increase in price ($175 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($32 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 2025
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Portland to London 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, Cheapflights users made 2,558,603 searches. Data last updated October 23, 2025.
Use the filters below to find and compare flights from Portland to London that are best for you.

Fly from

Portland

Fly to

London

Route

Depart

Return

Price

PortlandLondon

PWM - LHR

PWMLHR

Portland

Tue 11/18

2:30 pm-6:55 am

1 stop11h 25m

London Heathrow

Tue 11/25

6:30 am-10:19 pm

2 stops20h 49m

$594

PortlandLondon

PWM - LHR

PWMLHR

Portland

Tue 11/18

4:53 pm-8:45 am

1 stop10h 52m

London Heathrow

Tue 11/25

10:45 am-10:19 pm

1 stop16h 34m

$600

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 11/27

9:00 am-6:30 pm

2 stops28h 30m

London Heathrow

Wed 12/3

6:40 am-11:59 pm

2 stops22h 19m

$637

PortlandLondon

PWM - LHR

PWMLHR

Portland

Sun 12/7

4:53 pm-8:45 am

1 stop10h 52m

London Heathrow

Sun 12/14

8:55 am-10:23 pm

1 stop18h 28m

$642

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 12/11

2:34 pm-10:15 am

1 stop14h 41m

London Heathrow

Tue 12/16

9:00 am-11:59 pm

2 stops19h 59m

$643

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 11/27

9:00 am-9:40 pm

2 stops31h 40m

London Heathrow

Thu 12/4

5:00 pm-11:59 pm

2 stops35h 59m

$644

PortlandLondon

PWM - LHR

PWMLHR

Portland

Sun 12/7

12:53 pm-8:45 am

1 stop14h 52m

London Heathrow

Sun 12/14

11:45 am-11:59 pm

2 stops17h 14m

$644

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 11/27

9:00 am-9:40 pm

2 stops31h 40m

London Heathrow

Tue 12/2

10:20 am-11:59 pm

2 stops42h 39m

$644

PortlandLondon

PWM - LGW

PWMLGW

Portland

Thu 11/27

3:15 pm-10:00 am

2 stops37h 45m

London Gatwick

Fri 12/5

2:00 pm-10:36 am

1 stop25h 36m

$680

PortlandLondon

PWM - LCY

PWMLCY

Portland

Thu 2/19

2:35 pm-8:50 am

2 stops13h 15m

London City

Thu 2/26

10:00 am-9:59 pm

2 stops16h 59m

$708

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/21

Showing 1-10 of 24 results
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Compare providers for flights from Portland to London

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 London in October.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice Accuracy3 starsTrust Score*3 stars

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

Have a flexible travel schedule? Discover the best time to fly to London 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 London

What is the cheapest month to book a flight from Portland, Maine to London?

Currently, August is the cheapest month in which you can book a flight from Portland, Maine to London (average of $311). Flying from Portland, Maine to London in June is currently the most expensive (average of $552). 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 LON?

Find hourly flight availability from Portland to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated October 23, 2025.

Unlike at noon, when flights are generally more expensive, you can save up to 31% on flights from Portland, Maine to London by exploring options for tickets in the afternoon.

How much does it cost to fly round-trip from Portland, Maine to London?

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated October 23, 2025.
Get a feel of what it's like to fly with Delta, United Airlines, and JetBlue from Portland to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
7,981 reviews

Overall

7.9

Crew

8.5

Comfort

7.9

Boarding

8.2

Food

7.3

Entertainment

7.9

Reviews

1 / 20
8.0
Excellent

Matthew,Oct 2025

GSP - ATL

This is always a full flight since it is the connecting route to primary destinations through Atlanta. That said, the crew handles the full load well. Not much more to say, it is a short flight with no in-flight services due to the length.
Delta
7.9
Good
7,981 reviews
Delta
7.9
Good
7,981 reviews

Overall

7.9

Crew

8.5

Comfort

7.9

Boarding

8.2

Food

7.3

Entertainment

7.9

Reviews

1 / 20
8.0
Excellent

Matthew,Oct 2025

GSP - ATL

This is always a full flight since it is the connecting route to primary destinations through Atlanta. That said, the crew handles the full load well. Not much more to say, it is a short flight with no in-flight services due to the length.
United Airlines
7.4
Good
8,991 reviews
Delta
7.9
Good
7,981 reviews

Overall

7.9

Crew

8.5

Comfort

7.9

Boarding

8.2

Food

7.3

Entertainment

7.9

Reviews

1 / 20
8.0
Excellent

Matthew,Oct 2025

GSP - ATL

This is always a full flight since it is the connecting route to primary destinations through Atlanta. That said, the crew handles the full load well. Not much more to say, it is a short flight with no in-flight services due to the length.
JetBlue
7.2
Good
2,908 reviews
Delta
7.9
Good
7,981 reviews

Overall

7.9

Crew

8.5

Comfort

7.9

Boarding

8.2

Food

7.3

Entertainment

7.9

Reviews

1 / 20
8.0
Excellent

Matthew,Oct 2025

GSP - ATL

This is always a full flight since it is the connecting route to primary destinations through Atlanta. That said, the crew handles the full load well. Not much more to say, it is a short flight with no in-flight services due to the length.

Related info for your journey

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

  • What airport do you fly from for flights from Portland to London?

    Portland (PWM) is the airport you will fly out of if you book a flight from Portland to London. You should not have trouble finding flights to London from Portland; the airport handles an average of 0 outbound flights to London per day. You should also have plenty of airline options to choose from since 2 airlines have flights from the Portland airport to London. It is only a 2.9 mi journey to Portland (PWM) from Portland’s city center.

  • How long is the flight from Portland, Maine to London?

    There are many flights that can get you from Portland, Maine to London in 10h 52m. Fly via Delta, KLM, or Scandinavian Airlines to get the fastest option. There are 3173 mi between Portland, Maine and London. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from Portland, Maine to London round-trip?

    Flying on United Airlines is currently your cheapest option to London, with prices starting at $648. Another option worth looking into is Delta, starting at $825 round trip. United Airlines is 25% cheaper than the average price of flights available within the next 90 days to this destination.

  • What are the most popular routes from Portland, Maine to London?

    Most travelers choose Portland - London Heathrow, Portland - London City or Portland - London Gatwick when deciding on the best route from Portland, Maine to London.

  • Can I find deals for flights from Portland to London that include hotel bookings?

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

  • How can I find direct flights from Portland to London?

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

  • Can I find deals for business class flights from Portland to London?

    Yes. Cheapflights offers flight deals from Portland to London 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 London?

    Currently, August is the cheapest month in which you can book a flight from Portland, Maine to London (average of $311). Flying from Portland, Maine to London in June is currently the most expensive (average of $552). 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

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Hounslow
Ilford
Hayes
Southend-on-Sea
Harrow
Croydon
Eastleigh
Dartford
Dover
Winchester
Orpington
Gatwick
Borehamwood
Aylesbury
Bedford
Chipping Norton
Wembley
Folkestone
Eastbourne
Sutton

Browse thousands of different options on Cheapflights for your next trip

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Top 2 airlines flying from Portland to London

Discover the top 2 airlines that operate flights from Portland to London. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated October 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapest$648Average$924FlexibilityNo cancel feeOn-time69%
DeltaCheapest$825Average$963FlexibilityNo cancel feeOn-timeN/A

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