Cheapest return flights from Seattle to London in December from $838

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

Return flights

30 Dec - 21 Jan American Airlines direct
29 Dec - 10 Jan Brussels Airlines
30 Dec - 19 Jan Brussels Airlines
29 Dec - 10 Jan KLM direct
29 Dec - 05 Jan Icelandair
27 Dec - 29 Dec Condor
26 Dec - 29 Dec Aer Lingus
31 Dec - 04 Jan Icelandair
27 Dec - 05 Jan Air Canada
26 Dec - 03 Jan Air Canada
29 Dec - 05 Jan KLM direct
28 Dec - 03 Jan Lufthansa
27 Dec - 29 Dec British Airways direct
26 Dec - 29 Dec British Airways direct

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

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