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

Return flights

03 Dec - 10 Dec	Icelandair
03 Dec - 08 Dec	Icelandair
02 Dec - 08 Dec	Icelandair
01 Dec - 08 Dec	Icelandair
02 Dec - 09 Dec	Icelandair
04 Dec - 08 Dec	Icelandair
01 Dec - 09 Dec	Icelandair
31 Dec - 15 Jan	Iberia	direct
10 Dec - 16 Dec	British Airways
30 Dec - 13 Jan	Iberia
03 Dec - 10 Dec	American Airlines	direct
08 Dec - 24 Dec	British Airways	direct
16 Dec - 10 Jan	Icelandair
15 Dec - 10 Jan	Icelandair
24 Dec - 17 Jan	Icelandair
29 Dec - 24 Jan	Air Canada
15 Dec - 15 Jan	Icelandair
12 Dec - 11 Jan	Icelandair
30 Dec - 13 Jan	United	direct
28 Dec - 17 Jan	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 $479

Return flights