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

Return flights

28 Sep - 18 Oct	Scandinavian Airlines
18 Sep - 25 Sep	Aer Lingus	direct
04 Sep - 11 Sep	Icelandair
03 Sep - 11 Sep	Icelandair
02 Sep - 27 Sep	Icelandair
08 Sep - 16 Sep	Icelandair
30 Sep - 07 Oct	Icelandair
30 Sep - 09 Oct	Icelandair
02 Sep - 16 Sep	Icelandair
11 Sep - 25 Sep	Aer Lingus	direct
12 Sep - 19 Sep	United
17 Sep - 24 Sep	United
29 Sep - 06 Oct	Icelandair
14 Sep - 21 Sep	United
16 Sep - 14 Oct	Aer Lingus
27 Sep - 11 Oct	Icelandair
25 Sep - 18 Oct	Icelandair
13 Sep - 04 Oct	United
02 Sep - 02 Oct	Iberia
28 Sep - 06 Oct	Aer Lingus

Also check the deals for one-way flights from Seattle to Dublin in September.

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 September from 436€

Return flights