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

Return flights

03 Dec - 10 Dec	Air France
10 Dec - 14 Dec	Aer Lingus	direct
03 Dec - 10 Dec	Aer Lingus	direct
03 Dec - 12 Dec	SWISS
08 Dec - 15 Dec	Aer Lingus	direct
11 Dec - 15 Dec	KLM
14 Dec - 10 Jan	British Airways
07 Dec - 31 Dec	Iberia
16 Dec - 10 Jan	Air France
14 Dec - 31 Dec	British Airways
14 Dec - 29 Dec	British Airways
07 Dec - 31 Dec	Aer Lingus	direct
09 Dec - 04 Jan	Lufthansa
10 Dec - 04 Jan	Lufthansa
08 Dec - 04 Jan	Lufthansa
17 Dec - 10 Jan	Lufthansa
26 Dec - 04 Jan	British Airways
21 Dec - 10 Jan	Air Canada
07 Dec - 02 Jan	Air France
11 Dec - 04 Jan	Lufthansa

Also check the deals for one-way flights from Seattle to Dublin 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 Dublin in December from $422

Return flights