AirHint found the following cheapest return flights from Denver (DEN) to Lisbon (LIS) in July 2025 (see full year).

Return flights

28 Jul - 13 Aug	Aer Lingus
26 Jul - 03 Aug	Aer Lingus
07 Jul - 16 Jul	Air Canada
12 Jul - 17 Jul	Icelandair
01 Jul - 08 Jul	Lufthansa
08 Jul - 16 Jul	Turkish Airlines
08 Jul - 15 Jul	Air Canada
08 Jul - 17 Jul	Air Canada
15 Jul - 31 Jul	Delta
22 Jul - 28 Jul	Icelandair
21 Jul - 28 Jul	Air Canada
14 Jul - 21 Jul	Air Canada
28 Jul - 02 Aug	Aer Lingus
01 Jul - 07 Aug	Air France

Also check the deals for one-way flights from Denver to Lisbon in July.

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.

Book a cheap hotel in Lisbon

Cheap car rent in Lisbon

Cheapest return flights from Denver to Lisbon in July from $566

Return flights