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

Return flights

09 Dec - 16 Dec	TAP	direct
02 Dec - 12 Dec	TAP	direct
06 Dec - 13 Dec	Scandinavian Airlines
03 Dec - 10 Dec	TAP	direct
06 Dec - 13 Dec	TAP	direct
05 Dec - 08 Dec	Frontier Airlines
30 Dec - 06 Jan	TAP	direct
01 Dec - 11 Jan	Turkish Airlines
13 Dec - 06 Jan	TAP	direct
01 Dec - 11 Jan	TAP	direct
15 Dec - 10 Jan	Icelandair
13 Dec - 20 Dec	Icelandair
27 Dec - 29 Dec	Lufthansa
15 Dec - 10 Jan	TAP	direct
14 Dec - 06 Jan	TAP	direct
24 Dec - 28 Dec	Lufthansa
12 Dec - 06 Jan	United
25 Dec - 31 Dec	Scandinavian Airlines
12 Dec - 06 Jan	TAP	direct
27 Dec - 01 Jan	SWISS

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 467€

Return flights