Cheapest return flights from Seattle to London in December from 522€

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

Return flights

10 Dec - 17 Dec Icelandair
11 Dec - 17 Dec Icelandair
11 Dec - 17 Dec Air France direct
06 Dec - 07 Dec Scandinavian Airlines
13 Dec - 03 Jan Icelandair
30 Dec - 06 Jan United
30 Dec - 06 Jan British Airways direct
15 Dec - 20 Dec Icelandair
15 Dec - 30 Dec Icelandair
20 Dec - 10 Jan Icelandair
18 Dec - 17 Jan Icelandair
26 Dec - 02 Jan Air Canada
20 Dec - 27 Dec United
19 Dec - 28 Dec United
26 Dec - 02 Jan Delta direct
19 Dec - 26 Dec Air France direct
21 Dec - 27 Dec Icelandair
17 Dec - 04 Jan United
13 Dec - 03 Jan Air France direct
20 Dec - 10 Jan British Airways direct

Also check the deals for one-way 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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