Cheapest one-way flights from Seattle to London in December from $373

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

One-Way flights

31 Dec Icelandair
29 Dec Icelandair
30 Dec Icelandair
27 Dec EVA Air
28 Dec Air New Zealand
30 Dec Air France direct
31 Dec Air France direct
28 Dec Aer Lingus direct
25 Dec Lufthansa
25 Dec Aer Lingus direct

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

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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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