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

Return flights

05 Dec - 14 Dec	Icelandair
05 Dec - 12 Dec	Icelandair
11 Dec - 11 Jan	Icelandair
02 Dec - 09 Dec	Icelandair
12 Dec - 12 Jan	Icelandair
08 Dec - 15 Dec	Icelandair
11 Dec - 18 Dec	Icelandair
10 Dec - 15 Dec	Icelandair
02 Dec - 09 Dec	British Airways	direct
01 Dec - 09 Dec	Delta
11 Dec - 17 Dec	Icelandair
02 Dec - 16 Dec	United
28 Dec - 17 Jan	British Airways	direct
15 Dec - 10 Jan	British Airways	direct
11 Dec - 11 Jan	British Airways	direct
13 Dec - 12 Jan	United
27 Dec - 17 Jan	United
25 Dec - 08 Jan	United
29 Dec - 05 Jan	British Airways	direct
19 Dec - 11 Jan	Icelandair

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 457€

Return flights