Cheap flights from Portland to London from $318

The month of January is, on average, the cheapest month to fly to London Heathrow Airport from Portland, with most prices found around $687. If you’re not able to fly to London Heathrow Airport in January, then February is your next best option. Flight prices from Portland to London Heathrow Airport during February average around $689.

Our data shows that Monday is the least expensive day to fly to London Heathrow Airport. Tickets to fly out on this day can be as low as $848. The most expensive day to fly to London Heathrow Airport is Saturday, with ticket prices averaging around $1,015.

According to our data, the cheapest time of day to fly to London Heathrow Airport is in the afternoon. momondo users have found flights departing from Portland to London Heathrow Airport in the afternoon for as low as $735. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights in the evening are often more expensive with an average ticket price of $931.

Fly from Portland to London Heathrow for the best Portland - London Heathrow flight prices

You are more likely to see cheaper flights to London Heathrow Airport from Portland when booking weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around $867 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Portland for as low as $754 on momondo.

There are 4 cabin classes available to choose from on Portland to London Heathrow Airport flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

You could potentially save up to 18% on your flight if you consider stops on a Portland to London Heathrow Airport flight.

As of April 2026, prices for Portland to London Heathrow Airport flights are approximately 11% more expensive when compared to flights at the same time last year.

Delta, Icelandair, and WestJet are the most popular carriers operating from Portland to London Heathrow

British Airways, Icelandair and American Airlines are the top three most popular airlines that fly to London Heathrow Airport from Portland according to our data. British Airways is the first choice among our users, with 68% of people opting to fly with this airline when traveling to London Heathrow Airport. Keep in mind that there are 13 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.

Reykjavik (KEF) was the most common stop: 60% of momondo users choosing 1-stop flights on this route connected there.

Flights via Reykjavik (KEF) offer the lowest average round-trip price of $1,034.

Flights connecting via Seattle (SEA) have the shortest average one-way travel time: 13h 00m.

Seattle (SEA) has the shortest average layover time for this route: 2h 19m.

As of April 2026, 7 flights take off from Portland and land in London Heathrow Airport each day. The most common flight departure time for this route is 7:00PM, with 100% of daily flights taking off in the evening.

The number of flights available between Portland and London Heathrow Airport is 49 per week as of April 2026. The most frequent departure day is Mon, with 14% of weekly flights leaving on this day.