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

Return flights

04 May - 16 May	Icelandair
13 May - 20 May	Icelandair
08 May - 25 May	Icelandair
12 May - 06 Jun	Icelandair
19 May - 28 May	Icelandair
10 May - 24 May	Icelandair
13 May - 06 Jun	Icelandair
21 May - 09 Jun	Icelandair
14 May - 06 Jun	Icelandair
17 May - 25 May	Iberia
13 May - 25 May	Turkish Airlines
20 May - 29 May	Icelandair
21 May - 29 May	Icelandair
18 May - 13 Jun	SWISS
15 May - 06 Jun	Icelandair
21 May - 13 Jun	Icelandair
24 May - 01 Jun	TAP
29 May - 14 Jun	Porter Airlines (Canada) Ltd
29 May - 13 Jun	Porter Airlines (Canada) Ltd

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

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 May from $558

Return flights