AirHint found the following cheapest return flights from Denver (DEN) to Porto (OPO) in May 2026 (see full year).

Return flights

05 May - 12 May	Delta
06 May - 13 May	Delta
04 May - 11 May	British Airways
17 May - 24 May	Delta
09 May - 16 May	Turkish Airlines
07 May - 14 May	British Airways
03 May - 10 May	British Airways
02 May - 09 May	Delta
18 May - 25 May	British Airways
17 May - 04 Jun	British Airways
17 May - 01 Jun	British Airways
01 May - 08 May	United
31 May - 07 Jun	Icelandair
29 May - 05 Jun	SWISS
28 May - 04 Jun	United
30 May - 06 Jun	Icelandair

Also check the deals for one-way flights from Denver to Porto in May.

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 Porto in May from $616

Return flights