PWM - LON

$349 Find Cheap Flights from Portland to London

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Portland to London departing on 4/19. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to London

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Portland to London, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Portland to London, as well as popular online travel agencies
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Everything you should know

Cheapest round-trip
$715
Overall average: $789
United Airlines
Sat 2/28Mon 3/16
PWM - LHR • 1 stop
Cheapest one-way
$349
JetBlue
Sun 4/19
PWM - LHR • 1 stop
Top airlines
United Airlines
Cheapest • from $715 (round-trip)
Delta
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
October
Cheapest • 29% price drop
April
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to London!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Portland to London (PWM-LON)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Portland to London that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Portland to London

Sat, Feb 28 - Mon, Mar 16
United Airlines Logo
4:11 pm - 5:55 amPWM-LHR
32h 44m1 stop
United Airlines Logo
4:40 pm - 11:11 pmLHR-PWM
34h 31m2 stops
$715United Airlines
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Sat, Feb 28 - Mon, Mar 16
Delta Logo
2:35 pm - 8:10 pmPWM-LHR
24h 35m1 stop
Delta Logo
4:10 pm - 11:49 pmLHR-PWM
11h 39m1 stop
$748Delta
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Sat, Feb 28 - Mon, Mar 16
Air Canada Logo
7:31 pm - 6:30 amPWM-LHR
29h 59m2 stops
Air Canada Logo
1:25 pm - 1:57 pmLHR-PWM
28h 32m2 stops
$761Air Canada
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Mon, Apr 20 - Sat, Apr 25
JetBlue Logo
2:20 pm - 9:30 amPWM-LHR
14h 10m1 stop
JetBlue Logo
11:55 am - 1:23 pmLHR-PWM
30h 28m1 stop
$815JetBlue
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Mon, Apr 20 - Fri, Apr 24
JetBlue Logo
2:20 pm - 9:30 amPWM-LHR
14h 10m1 stop
JetBlue Logo
11:55 am - 1:23 pmLHR-PWM
30h 28m1 stop
$849JetBlue
Find Deal
Sat, Apr 18 - Sat, Apr 25
Delta Logo
11:25 am - 6:25 amPWM-LHR
14h 00m1 stop
Delta Logo
8:00 pm - 11:01 amLHR-PWM
20h 01m1 stop
$898Delta
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Sat, Apr 18 - Sat, Apr 25
Air Canada Logo
11:19 am - 10:00 amPWM-LHR
17h 41m2 stops
Air Canada Logo
9:30 am - 10:58 pmLHR-PWM
18h 28m2 stops
$918Air Canada
Find Deal
Sat, Feb 28 - Mon, Mar 16
Scandinavian Airlines Logo
2:35 pm - 4:25 pmPWM-LHR
20h 50m3 stops
Scandinavian Airlines Logo
6:40 am - 11:49 pmLHR-PWM
21h 09m2 stops
$935Scandinavian Airlines
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Sat, Feb 28 - Mon, Mar 16
Scandinavian Airlines Logo
2:35 pm - 4:25 pmPWM-LHR
20h 50m3 stops
Scandinavian Airlines Logo
6:40 am - 11:49 pmLHR-PWM
21h 09m3 stops
$942Scandinavian Airlines
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Tue, Nov 25 - Sun, Nov 30
United Airlines Logo
9:54 am - 6:40 amPWM-LHR
15h 46m1 stop
United Airlines Logo
6:00 pm - 11:17 pmLHR-PWM
34h 17m2 stops
$1,154United Airlines
Find Deal
Booking Insights

KAYAK's insights & trends for Portland to London flights

Get data-powered insights and trends into flights from Portland to London to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from Portland to London?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Portland to London, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Portland to London is October, where tickets cost $619 (return) on average. On the other hand, the most expensive months are June and July, where the average cost of round-trip tickets is $1,242 and $1,188 respectively.

Good to know

Low seasonFebruary
Cheapest flight$399
Best time to beat the crowds with an average 18% drop in price.
Most popular time to fly and prices are also 14% lower on average.
Flight from Portland to London

When to book flights from Portland to London

Are your dates flexible? Find out the best times to travel from Portland to London based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Portland to London

  • What is the cheapest flight from Portland to London?

    In the last 3 days, the lowest price for a flight from Portland to London was $349 for a one-way ticket and $715 for a round-trip.

  • Do I need a passport to fly between Portland and London?

    Yes

  • Which aircraft models fly most regularly from Portland to London?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Portland to London?

    SkyTeam, and Star Alliance are the airline alliances operating flights between Portland and London, with SkyTeam being the most commonly used for this route.

  • Which is the best airline for flights from Portland to London, Delta or United Airlines?

    The two airlines most popular with KAYAK users for flights from Portland to London are Delta and United Airlines. With an average price for the route of $793 and an overall rating of 7.9, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $853 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from Portland to London?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Portland to London.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Portland to London?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London from Portland is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Portland to London?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London with an airline and back to Portland with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Portland to London?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London from Portland up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 3 airlines serving from Portland to London

 
See real verified KAYAK customer reviews for airlines flying from Portland to London. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Portland to London? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.9
DeltaOverall score based on 8003 reviews
7.3Food
7.9Entertainment
8.2Boarding
7.9Comfort
8.5Crew
Airline reviews

I truly love flying with Delta. They have always treated me with the upmost respect

10.0 ExcellentMAYRA, Nov 2025JFK - MIA
Read more Delta reviews

I truly love flying with Delta. They have always treated me with the upmost respect

Our flight attendant in FIRST CLASS was one of the worst I’ve ever had. She was not at all pleasant, nor particularly good at her service.

Everything went well and was good. Nothing exceptional, but no complaints either. Cheap seats are pretty comfortable.

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

They ended up paying for the bag twice, but the counter wouldn't take my baggage receipt. Left it to me to resolve. Not sure how to resolve the issue.

The customer service before board was very rude and when I expressed my concerns about making the connecting flight she laughed and told me I bought the wrong ticket. I explained once it showed the flight was delayed it no longer let me change seats or anything. I was trying to upgrade to make sure I would get to the next gate on time.

Non stop on long haul is the way to go. Great experience

The aircraft interior is old and tired on this aircraft. The entertainment system never worked despite the crews attempt to reset the system.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Old plane and old configuration/seats but still comfortable for a morning flight

Other than a way way too cold cabinets for the entire flight, all was great

One bag is incorrect and not acceptable for an international flight. The food was not just good. I won't fly with them again.

Not pleasant trip cross country when the entertainment and WiFi system not working. No entertainment for entirety of route. Staff was rather nonchalant in that they dismissed the problem due to age of plane. It would have been nice to know this up front so I could have come prepared to read or download movies before boarding Coincidentally or not, there was a similar issue with the entertainment system on my previous flight I took on my fist leg of the trip. There are no seat TVs, so you must rely on the app when it works. United can do better. Also, what use it it to pay for boarding group 2 when half of the passengers are in the same line as you?

Plane boarded early a quickly, was mostly full. We left close to on time. And landed early.

My experience on this United Airlines flight was highly uncomfortable, primarily due to two issues: Cabin Temperature: The temperature on the Boeing 737 MAX 8 was unacceptably high, feeling consistently around 80 degrees throughout the flight. This made sleeping impossible and significantly detracted from the experience. Seating Arrangement: Being stuck in a middle seat for a six-and-a-half-hour overnight flight compounded the discomfort. Moving forward, I will always purchase a seat assignment to avoid this situation.

Premium Plus is a really good idea for longer flights

7 hours delayed due to operational issues on United’s end. Basically laziness.

Short flight but an "eager to help" crew made the journey more enjoyable!

Flight was delayed only slightly before takeoff due to traffic control. However, the flight arrived early to ORD. Good flight. United has been very reliable for me.

The person I bought the ticket for didn’t make the flight.

Checking In on JetBlue site was impossible. It hung up on REAL ID. Even my Global Entry did not help. Luckily, on Kayak site it was a breeze. Entire flight the temperature was COLD! Otherwise the crew was great!

The flight was two hours late due to a computer fault and resulting maintenance. Nothing was offered as compensation beyond bottles of water during the time we were deplaned and waiting in the terminal.

Very pleasant flight attendants. Gate crew rather loud chatting with each other.

Four plus hour flight delay in New York caused us to take off after 11:30pm. We didn’t arrive at our hotel until five hours after check in. Started the trip off feeling exhausted.

Plane was in bad shape. TV’s and WiFi didn’t work. Plane need a refresh. Not enough room for bags.

There was a fowl odour coming from the lavatory the entire flight

Everything was great. I liked the text updates so that I never miss a gate change & I have all the latest info.

I don’t usually fly budget airlines or airlines in the United States. It was as good as any other airline. The seats are comfortable and the airline attendants are not rude & surly. Very nice flight (s).

No internet on a flight over three hours in this age is criminal. Staff inattentive and dismissive

They have the most inexperienced / rude flight staff I’ve encountered

Everything you need to know for your flight from Portland to London

Information on your arrival and departure airports