AirHint found the following cheapest return flights from Washington (DCA) to Lisbon (LIS) in December 2025 (see full year).

Return flights

08 Dec - 15 Dec	Scandinavian Airlines
04 Dec - 08 Dec	Scandinavian Airlines
02 Dec - 12 Dec	Air Canada
03 Dec - 27 Dec	British Airways
24 Dec - 17 Jan	British Airways
16 Dec - 06 Jan	British Airways
26 Dec - 17 Jan	Air France
22 Dec - 10 Jan	Scandinavian Airlines
18 Dec - 25 Dec	United
24 Dec - 03 Jan	Scandinavian Airlines
19 Dec - 27 Dec	British Airways
18 Dec - 27 Dec	British Airways
17 Dec - 23 Dec	TAP
18 Dec - 23 Dec	TAP
18 Dec - 06 Jan	British Airways
09 Dec - 03 Jan	British Airways
02 Dec - 05 Dec	Air Canada

Also check the deals for one-way flights from Washington to Lisbon in December.

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 Washington to Lisbon in December from 632€

Return flights