Cheapest return flights from Seattle to London in December from $622

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 December 2025 (see full year).

Return flights

08 Dec - 22 Dec Icelandair
11 Dec - 25 Dec Icelandair
08 Dec - 22 Dec Air France direct
11 Dec - 25 Dec Air France direct
05 Dec - 13 Dec Icelandair
01 Dec - 07 Jan Lufthansa
05 Dec - 13 Dec KLM direct
01 Dec - 07 Jan British Airways direct
25 Dec - 08 Jan Icelandair
01 Dec - 31 Dec Icelandair
23 Dec - 30 Dec Delta direct
01 Dec - 31 Dec British Airways direct
25 Dec - 08 Jan Air France direct
22 Dec - 05 Jan Air Canada
18 Dec - 02 Jan Icelandair
20 Dec - 03 Jan Icelandair
20 Dec - 03 Jan Delta direct
18 Dec - 02 Jan British Airways direct

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

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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