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

Return flights

29 Dec - 07 Jan	Air Canada
03 Dec - 08 Dec	jetBlue
05 Dec - 10 Dec	Air Canada
10 Dec - 16 Dec	British Airways
03 Dec - 11 Dec	British Airways
04 Dec - 08 Dec	jetBlue
04 Dec - 07 Dec	jetBlue
04 Dec - 09 Dec	Air Canada
29 Dec - 24 Jan	jetBlue
27 Dec - 14 Jan	British Airways
27 Dec - 15 Jan	British Airways
23 Dec - 07 Jan	Iberia
11 Dec - 16 Dec	jetBlue
28 Dec - 17 Jan	jetBlue
10 Dec - 07 Jan	British Airways
15 Dec - 09 Jan	British Airways
15 Dec - 10 Jan	jetBlue
16 Dec - 10 Jan	jetBlue
11 Dec - 15 Dec	jetBlue
01 Dec - 27 Dec	Air Canada

Also check the deals for one-way flights from Washington to London 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 London in December from $587

Return flights