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

Return flights

04 Dec - 11 Dec	Icelandair
03 Dec - 17 Jan	Icelandair
05 Dec - 16 Dec	Icelandair
09 Dec - 16 Dec	Icelandair
11 Dec - 25 Dec	Icelandair
03 Dec - 17 Dec	Icelandair
05 Dec - 15 Dec	Icelandair
03 Dec - 07 Dec	Aer Lingus
11 Dec - 25 Dec	Condor	direct
24 Dec - 31 Dec	Icelandair
09 Dec - 16 Dec	Lufthansa	direct
18 Dec - 01 Jan	Condor	direct
29 Dec - 05 Jan	Lufthansa	direct
18 Dec - 05 Jan	British Airways
18 Dec - 05 Jan	Condor	direct

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

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 Frankfurt in December from 510€

Return flights