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

Return flights

30 Dec - 13 Jan	Icelandair
21 Dec - 06 Jan	Frontier Airlines
21 Dec - 07 Jan	Frontier Airlines
23 Dec - 06 Jan	Icelandair
22 Dec - 29 Dec	Frontier Airlines
17 Dec - 24 Dec	Frontier Airlines
18 Dec - 05 Jan	Copa
19 Dec - 03 Jan	Frontier Airlines
21 Dec - 04 Jan	Frontier Airlines
23 Dec - 04 Jan	Icelandair
19 Dec - 22 Dec	Air Canada
19 Dec - 02 Jan	Austrian Airlines
22 Dec - 02 Jan	Frontier Airlines
20 Dec - 28 Dec	Frontier Airlines
21 Dec - 28 Dec	Brussels Airlines
20 Dec - 23 Dec	Air Canada
23 Dec - 26 Dec	Air Canada
21 Dec - 30 Dec	KLM
21 Dec - 27 Dec	jetBlue
24 Dec - 27 Dec	Air Canada

Also check the deals for one-way flights from Denver to London 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 London in December from $834

Return flights