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

Return flights

07 Dec - 14 Dec	Icelandair
02 Dec - 09 Dec	Icelandair
03 Dec - 10 Dec	Icelandair
01 Dec - 10 Dec	Icelandair
03 Dec - 10 Dec	Aer Lingus	direct
01 Dec - 10 Dec	Aer Lingus	direct
01 Dec - 08 Dec	Icelandair
01 Dec - 08 Dec	Aer Lingus	direct
08 Dec - 15 Dec	United
11 Dec - 05 Jan	British Airways
13 Dec - 20 Dec	Icelandair
10 Dec - 04 Jan	Lufthansa
19 Dec - 10 Jan	British Airways
14 Dec - 04 Jan	British Airways
13 Dec - 03 Jan	Icelandair
22 Dec - 04 Jan	British Airways
20 Dec - 02 Jan	Delta
27 Dec - 03 Jan	United
10 Dec - 04 Jan	Aer Lingus	direct
14 Dec - 03 Jan	Air France

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 387€

Return flights