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

Return flights

25 Jul - 21 Aug	KLM
28 Jul - 05 Aug	KLM
28 Jul - 13 Aug	KLM
29 Jul - 05 Aug	KLM
22 Jul - 21 Aug	ITA Airways
20 Jul - 21 Aug	ITA Airways
21 Jul - 21 Aug	ITA Airways
31 Jul - 05 Aug	Delta
23 Jul - 21 Aug	KLM
24 Jul - 21 Aug	ITA Airways
22 Jul - 29 Jul	SWISS
23 Jul - 29 Jul	Lufthansa
20 Jul - 27 Jul	SWISS
21 Jul - 31 Jul	KLM
21 Jul - 30 Jul	Lufthansa
26 Jul - 31 Jul	SWISS
23 Jul - 30 Jul	Lufthansa
24 Jul - 29 Jul	Turkish Airlines
24 Jul - 31 Jul	Lufthansa
22 Jul - 28 Jul	ITA Airways

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

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 July from $748

Return flights