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

Return flights

13 Jan - 20 Jan	British Airways	direct
30 Jan - 13 Feb	Air France
23 Jan - 30 Jan	British Airways	direct
30 Jan - 13 Feb	British Airways	direct
03 Jan - 10 Jan	Icelandair
03 Jan - 10 Jan	British Airways	direct

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 $515

Return flights