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

Return flights

01 Dec - 04 Dec	Icelandair
01 Dec - 08 Dec	Icelandair
03 Dec - 07 Dec	Icelandair
03 Dec - 10 Dec	Icelandair
12 Dec - 17 Dec	Air Canada
30 Dec - 24 Jan	Icelandair
07 Dec - 16 Dec	Icelandair
09 Dec - 16 Dec	Icelandair
12 Dec - 12 Jan	Frontier Airlines
10 Dec - 16 Dec	Icelandair
30 Dec - 13 Jan	Icelandair
15 Dec - 10 Jan	Icelandair
28 Dec - 17 Jan	Icelandair
22 Dec - 17 Jan	Icelandair
27 Dec - 08 Jan	Frontier Airlines
26 Dec - 07 Jan	Frontier Airlines
25 Dec - 31 Dec	Turkish Airlines
11 Dec - 19 Dec	Turkish Airlines
22 Dec - 07 Jan	Frontier Airlines
21 Dec - 07 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 401€

Return flights