Cheapest return flights from Washington to London in September from $611

Best time to book flights for Washington (IAD) to London (LHR) flights at AirHint

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

Return flights

10 Sep - 20 Sep Scandinavian Airlines
05 Sep - 21 Sep Scandinavian Airlines
23 Sep - 30 Sep United
05 Sep - 20 Sep Scandinavian Airlines
23 Sep - 30 Sep United direct
12 Sep - 27 Sep Icelandair
11 Sep - 25 Sep Icelandair
02 Sep - 09 Sep United direct
19 Sep - 25 Sep British Airways direct
06 Sep - 13 Sep Icelandair

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

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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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