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

Return flights

05 Oct - 20 Oct	Icelandair
08 Oct - 15 Oct	Aer Lingus
01 Oct - 08 Oct	Aer Lingus
08 Oct - 16 Oct	Aer Lingus
03 Oct - 18 Oct	Icelandair
21 Oct - 01 Nov	Icelandair
16 Oct - 21 Oct	Air Canada
08 Oct - 13 Oct	Air Canada
02 Oct - 09 Oct	Icelandair
07 Oct - 14 Oct	Icelandair
23 Oct - 30 Oct	Icelandair
26 Oct - 02 Nov	British Airways	direct
27 Oct - 03 Nov	British Airways	direct
22 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 $478

Return flights