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

Return flights

05 Oct - 15 Oct	Lufthansa
01 Oct - 09 Oct	Aer Lingus
08 Oct - 15 Oct	Aer Lingus
20 Oct - 27 Oct	Air Canada
15 Oct - 22 Oct	Lufthansa
21 Oct - 28 Oct	British Airways	direct
15 Oct - 22 Oct	British Airways	direct
29 Oct - 05 Nov	British Airways	direct
01 Oct - 09 Oct	British Airways	direct
27 Oct - 07 Nov	British Airways	direct
05 Oct - 15 Oct	British Airways	direct
24 Oct - 31 Oct	Icelandair
09 Oct - 20 Nov	Delta
26 Oct - 01 Nov	Icelandair
26 Oct - 01 Nov	British Airways	direct

Also check the deals for one-way flights from Denver to London in October.

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 October from 406€

Return flights