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Cheap flights from Portland, Maine to London from £333

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 5/1. Fares are subject to change and may not be available on all flights or dates of travel.
PWM — LON
31 Dec — 7 Jan1
1 adult
1 adult, Economy, 0 bags

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 1 December 2025.

Round-trip from

£452

One-way from

£333

Popular in

June

Cheapest in

October

Average price

£528
Delta
  • Delta
  • 13/1-20/1
  • 3 total stops
  • 29h 10m total
  • Portland to London
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United Airlines
  • United Airlines
  • 5/1
  • 2 total stops
  • 24h 45m total
  • Portland to London
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (£104 potential increase over avg. return price).
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Cheapest flight prices on average. 4% potential price decrease (£20 potential savings vs. average return price).
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Average for round-trip flights in December 2025
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Find flight deals from Portland to London

Enter your travel dates to find the best prices.

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 1 December 2025.

Sun 14/1219:46PWM - LHR
2 stops30h 24mAir Canada
Tue 23/1209:00LHR - PWM
2 stops43h 22mAir Canada
Deal found 29/11£517
Sat 6/1206:00PWM - LHR
1 stop10h 20mUnited Airlines
Thu 11/1206:35LHR - PWM
2 stops21h 34mUnited Airlines
Deal found 29/11£530
Sun 14/1214:13PWM - LHR
1 stop11h 27mUnited Airlines
Tue 23/1215:10LHR - PWM
1 stop13h 12mUnited Airlines
Deal found 29/11£534
Sat 6/1206:00PWM - LHR
1 stop10h 20mUnited Airlines
Fri 12/1218:00LHR - PWM
2 stops34h 12mUnited Airlines
Deal found 29/11£539
Sun 14/1206:00PWM - LHR
1 stop9h 35mUnited Airlines
Mon 22/1216:20LHR - PWM
1 stop12h 39mUnited Airlines
Deal found 30/11£572
Mon 15/1210:35PWM - LHR
1 stop19h 30mAustrian Airlines
Mon 22/1218:00LHR - PWM
1 stop29h 11mAustrian Airlines
Deal found 30/11£574
Mon 15/1206:00PWM - LHR
2 stops18h 55mUnited Airlines
Mon 22/1216:20LHR - PWM
2 stops26h 19mUnited Airlines
Deal found 29/11£575
Sat 13/1216:25PWM - LHR
1 stop32h 30mUnited Airlines
Mon 22/1216:20LHR - PWM
1 stop12h 39mUnited Airlines
Deal found 30/11£576
Sat 6/1206:00PWM - LHR
2 stops20h 10mAir Canada
Sat 13/1213:25LHR - PWM
2 stops24h 45mAir Canada
Deal found 29/11£583
Sat 6/1218:18PWM - LGW
2 stops30h 42mMultiple Airlines
Thu 11/1214:00LGW - PWM
1 stop24h 06mMultiple Airlines
Deal found 29/11£790
Sat 6/1218:18PWM - LGW
2 stops30h 42mMultiple Airlines
Fri 12/1214:00LGW - PWM
1 stop25h 36mMultiple Airlines
Deal found 29/11£820
Sat 13/1211:16PWM - LGW
1 stop17h 49mMultiple Airlines
Sun 21/1214:10LGW - PWM
1 stop23h 56mMultiple Airlines
Deal found 30/11£863

Cheapflights Fare Finder

 
Customise 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 858,174 searches. Data last updated 1 December 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 13/1

14:35-06:55

1 stop11h 20m

London Heathrow

Tue 20/1

11:30-00:20

2 stops17h 50m

£452

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 14/1

14:35-06:55

1 stop11h 20m

London Heathrow

Wed 21/1

09:00-00:20

2 stops20h 20m

£452

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 14/1

05:30-07:50

1 stop21h 20m

London Heathrow

Sat 24/1

06:30-22:27

2 stops20h 57m

£455

PortlandLondon

PWM - LHR

PWMLHR

Portland

Tue 13/1

06:17-09:20

3 stops22h 03m

London Heathrow

Tue 20/1

06:40-00:20

2 stops22h 40m

£456

PortlandLondon

PWM - LHR

PWMLHR

Portland

Tue 13/1

05:30-07:50

1 stop21h 20m

London Heathrow

Tue 20/1

08:55-22:27

1 stop18h 32m

£456

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 14/1

14:35-08:05

1 stop12h 30m

London Heathrow

Wed 21/1

10:45-22:27

1 stop16h 42m

£457

PortlandLondon

PWM - LHR

PWMLHR

Portland

Tue 5/5

12:50-09:05

2 stops15h 15m

London Heathrow

Wed 13/5

09:55-23:59

2 stops19h 04m

£468

PortlandLondon

PWM - LHR

PWMLHR

Portland

Fri 23/1

12:20-08:45

1 stop15h 25m

London Heathrow

Tue 27/1

08:55-00:20

2 stops20h 25m

£471

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 14/1

06:17-08:05

1 stop20h 48m

London Heathrow

Sat 24/1

16:35-23:59

1 stop12h 24m

£475

PortlandLondon

PWM - LCY

PWMLCY

Portland

Fri 23/1

14:35-09:30

2 stops13h 55m

London City

Tue 27/1

10:00-00:20

2 stops19h 20m

£496

Flights are sorted by cheapest return flights first.

Deals found on 28/11

Showing 1-10 of 30 results
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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 return 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 £235). Flying from Portland, Maine to London in June is currently the most expensive (average of £424). 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’s the top stopover airport for flights from Portland, Maine to London?

Share of one-stop return flights from Portland, Maine to London chosen by Cheapflights users in the past 12 months, using the same stopover each way.

Newark (EWR) – chosen by Cheapflights users on 40% of one-stop itineraries from Portland, Maine to London on Cheapflights.

What’s the cheapest stopover airport for flights from Portland, Maine to London?

Average return fare for one-stop flights from Portland, Maine to London, chosen by Cheapflights users in the past 12 months, with the same stopover each way.

New York (JFK) is the most affordable one-stop option, with an average return flight price of £485.

What’s the fastest stopover option from Portland, Maine to London?

Shortest average travel time for one-stop one-way flights from Portland, Maine to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by stopover airport.

Flights via Newark (EWR) have the shortest average one-way travel time for one-stop routes: 9h 40m.

Which airport typically offers the quickest stopover for flights from Portland, Maine to London?

Average stopover duration for one-stop one-way flights from Portland, Maine to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Newark (EWR) offer the fastest connection on this route, with an average stopover time of 1h 35m.

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 0 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 11h 20m. Fly via Delta or Scandinavian Airlines to get the fastest option. The distance between Portland, Maine and London is about 3173 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    The most popular flight routes from Portland, Maine to London are Portland - London Heathrow, Portland - London Gatwick and Portland - London City.

  • 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 holiday 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 £235). Flying from Portland, Maine to London in June is currently the most expensive (average of £424). 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

Travelling to a place near London?

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Why should you use Cheapflights to find cheap flight tickets from Portland to London?

Cheapflights helps you find that perfect flight to London from Portland by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Portland to London with no change fees?

Certainly. Search results for flights to London from Portland shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from Portland to London become cheaper?

Yes, Cheapflights offers price alerts on Portland to London flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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