AirHint found the following cheapest return flights from Seattle (SEA) to London (STN) in May 2026 (see full year).

Return flights

05 May - 19 May	Icelandair
01 May - 10 May	Icelandair
06 May - 30 May	Aer Lingus
11 May - 23 May	Icelandair
10 May - 14 May	Icelandair
24 May - 01 Jun	Aer Lingus
13 May - 19 May	Aer Lingus
23 May - 30 May	Aer Lingus
31 May - 08 Jun	Icelandair
22 May - 06 Jun	Icelandair
30 May - 06 Jun	Icelandair
27 May - 24 Jun	Icelandair
30 May - 09 Jun	Icelandair

Also check the deals for one-way flights from Seattle to London in May.

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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Cheapest return flights from Seattle to London in May from 576€

Return flights