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

Return flights

01 Dec - 09 Dec	Icelandair
02 Dec - 09 Dec	Icelandair
10 Dec - 17 Dec	Lufthansa
01 Dec - 10 Dec	Icelandair
29 Dec - 24 Jan	Lufthansa
05 Dec - 09 Dec	American Airlines
02 Dec - 18 Dec	Lufthansa
12 Dec - 17 Dec	United
08 Dec - 15 Dec	Icelandair
05 Dec - 13 Dec	Air Canada
06 Dec - 10 Dec	jetBlue
15 Dec - 06 Jan	Delta
07 Dec - 06 Jan	Delta
25 Dec - 06 Jan	Delta
27 Dec - 06 Jan	Delta
28 Dec - 06 Jan	Delta
24 Dec - 06 Jan	Delta
16 Dec - 06 Jan	Delta
29 Dec - 05 Jan	Lufthansa
21 Dec - 10 Jan	Air Canada

Also check the deals for one-way flights from Denver 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 Denver to Dublin in December from $372

Return flights