Cheap flights from Seattle to London from $272 BFI, SEA → LGW, LHR, STN
Boeing Field International Airport (BFI), Seattle-Tacoma International Airport (SEA) → London Gatwick Airport (LGW), London Heathrow Airport (LHR), Stansted Airport (STN)
The cheapest one-way found recently is $272 with Icelandair, 17 Mar 2027, found 4 days ago.
- Cheapest one-way found recently
- $272, found 4 days ago
- Cheapest month to fly
- March 2027, one-way fares from $272 found in the last 7 days
One-way
The cheapest one-way fare on each of 3 departure dates is usually $425 to $737.
Cheapest one-way found recently
$272
17 Mar 2027 · Icelandair
Seattle-Tacoma International Airport (SEA) → London Heathrow Airport (LHR)
Leaves 3:35 p.m. · 20 h 55 min trip
1 stop
found 4 days ago
Cheapest nonstop one-way
None seen yet.
Found recently, and the cheapest we hold
$272 17 Mar 2027found 4 days agoOpen this trip
It is also the cheapest one-way we hold, of any age.
What have prices looked like?
Over 35 days, 28 Sept to 11 Nov, the cheapest one-way we saw each day was $245 to $680.
Those were the prices on those days, not today's.
Is this a good one-way price?
Compared with the cheapest one-way fare on each of 3 departure dates from 23 Nov to 17 Mar 2027, found by travelers' searches in the last 7 days (economy, the price the seller showed on Aviasales). The usual range is the middle half of those prices.
Could nearby dates be cheaper?
We hold no other one-way fares leaving within 3 days of 17 Mar 2027 to compare.
Every date we hold
4 fares on 3 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 23 Nov | $577 | SeaPort Airlines | Boeing Field International Airport (BFI) → London Gatwick Airport (LGW) | 2 stops | found 4 days ago | Open this trip |
| 3 Jan 2027 | $897 | SeaPort Airlines | Boeing Field International Airport (BFI) → Stansted Airport (STN) | 3 stops | found 6 days ago | Open this trip |
| 17 Mar 2027 | $272 | Icelandair | Seattle-Tacoma International Airport (SEA) → London Heathrow Airport (LHR) | 1 stop | found 4 days ago | Open this trip |
Which month looks cheapest?
March 2027 is the cheapest month — from $272.
Airlines on the cheapest dates: SeaPort Airlines, Icelandair.
Premium cabin fares from Seattle to London
We hold no premium economy, business or first-class fares for this route: we collect them for the busiest routes, and this one is not among them yet.
Today's prices for 17 Mar 2027 in another cabin: Premium economy · Business · First
How far ahead were prices cheapest for Seattle to London?
One-way
Fares 180 or more days before departure were typically 17% lower than 30 to 59 days before departure.
From the cheapest one-way each day between 28 Sept and 11 Nov (35 days), grouped by how many days ahead the flight left; one adult in economy.
Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.
Prices reflect recent searches — current fares may differ.
See these ranges as a table
| Booked ahead by | Typical fare | Cheapest day | Above the cheapest | Days of prices |
|---|---|---|---|---|
| 30–59 days | $369 | $302 | +21% | 14 |
| 60–89 days | $331 | $331 | +8% | 13 |
| 90–179 days | $680 | $272 | +122% | 10 |
| 180+ days | $306 | $269 | Cheapest seen | 16 |
Could a nearby airport be cheaper?
A different airport at either end can change the fare — sometimes a lot.
One-way
Everett → London
34 km from Seattle
$512
$240 more than flying from Seattle
17 Mar 2027 · PAE → LHR · 1 stop
found 4 days ago
Cheapest recent price on each route — one way, per traveler in Economy. Distances are in a straight line.
Live price for these dates
The cheapest one-way found recently is for 17 Mar 2027. A live search on this page shows what those dates cost now, for one adult in economy.
Questions about this trip
How much is a one-way flight from Seattle to London?
The cheapest one-way found recently is $272 with Icelandair, 17 Mar 2027, found 4 days ago. The cheapest one-way fare on each of 3 departure dates is usually $425 to $737.
What is the cheapest month to fly from Seattle to London?
March 2027 is the cheapest month for a one-way, from $272, 17 Mar 2027, found 4 days ago.
How far ahead should I book a flight from Seattle to London?
In 35 days of prices between 28 Sept and 11 Nov, one-way fares 180 or more days before departure were typically 17% lower than 30 to 59 days before departure.
How long is the flight from Seattle to London?
The cheapest one-way found recently, with Icelandair on 17 Mar 2027, takes 20 h 55 min with 1 stop.
Which airlines have the cheapest flights from Seattle to London?
Between 23 Nov and 17 Mar 2027, SeaPort Airlines has the cheapest one-way on 2 of the 3 departure dates we hold, and Icelandair on 1.
Prices are what travelers' searches on Aviasales found in the last 7 days, in US dollars: the price the seller showed on Aviasales; bags may cost extra. Fares change, so check today's price before you book. How our prices work