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

Return flights

04 Dec - 11 Dec	Icelandair
02 Dec - 09 Dec	Icelandair
01 Dec - 10 Jan	Icelandair
03 Dec - 10 Dec	Icelandair
10 Dec - 17 Dec	Aer Lingus	direct
05 Dec - 13 Dec	Icelandair
03 Dec - 10 Dec	Aer Lingus	direct
01 Dec - 22 Dec	British Airways
01 Dec - 17 Dec	Aer Lingus	direct
16 Dec - 10 Jan	United
15 Dec - 22 Dec	Aer Lingus
06 Dec - 13 Dec	Icelandair
16 Dec - 06 Jan	Delta
22 Dec - 10 Jan	Icelandair
21 Dec - 09 Jan	Iberia
12 Dec - 05 Jan	Alaska Airlines
23 Dec - 10 Jan	Delta
17 Dec - 10 Jan	Alaska Airlines
30 Dec - 06 Jan	Icelandair
12 Dec - 04 Jan	Alaska Airlines

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 327€

Return flights