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

Return flights

09 Jan - 31 Jan	Icelandair
23 Jan - 26 Jan	Icelandair
06 Jan - 16 Jan	Icelandair
06 Jan - 14 Jan	Icelandair
29 Jan - 09 Feb	Icelandair
22 Jan - 29 Jan	Icelandair
08 Jan - 13 Jan	Icelandair
16 Jan - 19 Jan	Icelandair
08 Jan - 31 Jan	Icelandair
08 Jan - 20 Jan	Icelandair
15 Jan - 06 Feb	Icelandair
27 Jan - 21 Feb	Turkish Airlines
30 Jan - 21 Feb	Turkish Airlines
22 Jan - 23 Jan	Alaska Airlines
15 Jan - 07 Feb	Alaska Airlines

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

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 January from $486

Return flights