Cheapest one-way flights from Seattle to London in September from $258

Best time to book flights for Seattle (SEA) to London (LHR) flights at AirHint

AirHint found the following cheapest one-way flights from Seattle (SEA) to London (LHR) in September 2025 (see full year).

One-Way flights

29 Sep Icelandair
18 Sep Icelandair
19 Sep Icelandair
10 Sep Icelandair
15 Sep Alaska Airlines
29 Sep Air France direct
18 Sep Iberia direct
19 Sep British Airways direct
05 Sep Air France direct
06 Sep Air France direct

Also check the deals for return flights from Seattle to London in September.

Skyscanner

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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