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

Return flights

29 Sep - 25 Oct	Lufthansa
03 Sep - 17 Sep	Lufthansa
09 Sep - 16 Sep	United
06 Sep - 15 Sep	Lufthansa
03 Sep - 11 Sep	Air Canada
03 Sep - 10 Sep	United
05 Sep - 15 Sep	Air Canada
11 Sep - 04 Oct	Air Canada
04 Sep - 21 Sep	Lufthansa
05 Sep - 14 Sep	Air Canada
06 Sep - 20 Sep	Air Canada
06 Sep - 14 Sep	Air Canada
18 Sep - 11 Oct	Iberia

Also check the deals for one-way flights from Portland 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 Portland to Dublin in September from $559

Return flights