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

Return flights

01 May - 03 May	Scandinavian Airlines
07 May - 10 May	Scandinavian Airlines
06 May - 12 May	Icelandair
04 May - 11 May	Icelandair
01 May - 08 May	Icelandair
05 May - 12 May	Icelandair
08 May - 15 May	Icelandair
04 May - 10 May	Icelandair
01 May - 10 May	Icelandair
04 May - 14 May	Icelandair
18 May - 07 Jun	Icelandair
19 May - 05 Jun	Icelandair
25 May - 03 Jun	TAP
22 May - 07 Jun	Scandinavian Airlines
27 May - 19 Jun	Icelandair
26 May - 19 Jun	Icelandair
23 May - 12 Jun	Icelandair
28 May - 07 Jun	Icelandair
28 May - 08 Jun	Icelandair
31 May - 09 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 $486

Return flights