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

Return flights

05 Oct - 10 Oct	Icelandair
01 Oct - 07 Oct	Air Canada
29 Oct - 12 Nov	Air Canada
14 Oct - 21 Oct	United
05 Oct - 29 Oct	United
19 Oct - 27 Oct	Frontier Airlines
02 Oct - 16 Oct	Icelandair
24 Oct - 31 Oct	United
01 Oct - 04 Oct	United
05 Oct - 13 Oct	Aer Lingus
02 Oct - 04 Oct	United

Also check the deals for one-way flights from Denver to Barcelona 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 Barcelona in October from 350€

Return flights