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

Return flights

09 May - 15 May	Icelandair
08 May - 15 May	Icelandair
01 May - 07 May	Icelandair
12 May - 26 May	Icelandair
13 May - 31 May	Icelandair
15 May - 17 May	Icelandair
13 May - 20 May	Icelandair
05 May - 12 May	Icelandair
04 May - 15 May	Icelandair
07 May - 10 May	Icelandair
10 May - 09 Jun	Icelandair
18 May - 02 Jun	Icelandair
16 May - 01 Jun	Icelandair
27 May - 19 Jun	Icelandair
27 May - 11 Jun	Icelandair
29 May - 19 Jun	Icelandair
30 May - 10 Jun	Icelandair
25 May - 09 Jun	Icelandair
29 May - 09 Jun	Porter Airlines (Canada) Ltd
28 May - 19 Jun	Icelandair

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 444€

Return flights