AirHint found the following cheapest return flights from Washington (IAD) to London (LHR) in January 2026 (see full year).

Return flights

30 Jan - 04 Feb	TAP
24 Jan - 31 Jan	TAP
20 Jan - 31 Jan	TAP
22 Jan - 26 Jan	TAP
21 Jan - 26 Jan	TAP
23 Jan - 25 Jan	TAP
23 Jan - 26 Jan	TAP
21 Jan - 28 Jan	TAP
21 Jan - 29 Jan	TAP
20 Jan - 26 Jan	TAP
19 Jan - 26 Jan	TAP
23 Jan - 01 Feb	TAP
25 Jan - 02 Feb	Icelandair
29 Jan - 11 Feb	Icelandair
31 Jan - 04 Feb	Icelandair
28 Jan - 01 Feb	Icelandair
30 Jan - 01 Feb	Icelandair
11 Jan - 08 Feb	TAP
31 Jan - 05 Feb	Icelandair
28 Jan - 02 Feb	Icelandair

Also check the deals for one-way flights from Washington to London in January.

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 January from $423

Return flights