Cheapest return flights from Seattle to London in September from 574€

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

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

Return flights

28 Sep - 08 Oct Iberia direct
30 Sep - 08 Oct Iberia direct
21 Sep - 30 Sep Iberia direct
01 Sep - 30 Sep Scandinavian Airlines
30 Sep - 07 Oct Icelandair
23 Sep - 11 Oct Icelandair
08 Sep - 06 Oct Icelandair
05 Sep - 09 Sep Scandinavian Airlines
23 Sep - 11 Oct Air France direct
17 Sep - 10 Oct Iberia direct
19 Sep - 27 Sep Iberia direct
10 Sep - 17 Sep United
01 Sep - 30 Sep Air France direct
20 Sep - 27 Sep United
05 Sep - 09 Sep Iberia direct
08 Sep - 06 Oct Air France direct
12 Sep - 21 Sep Icelandair
12 Sep - 21 Sep Delta direct

Also check the deals for one-way 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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