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

Return flights

25 Aug - 02 Sep	Air Canada
13 Aug - 22 Aug	Air Canada
13 Aug - 26 Aug	Air Canada
19 Aug - 27 Aug	Air Canada
20 Aug - 28 Aug	Air Canada
05 Aug - 27 Aug	American Airlines
19 Aug - 26 Aug	Virgin Atlantic
11 Aug - 05 Sep	American Airlines
13 Aug - 21 Aug	Finnair
06 Aug - 20 Aug	Delta
05 Aug - 12 Aug	Air Canada
22 Aug - 26 Aug	Air Canada
12 Aug - 13 Sep	British Airways
27 Aug - 07 Sep	British Airways
22 Aug - 15 Sep	KLM
22 Aug - 01 Sep	American Airlines
21 Aug - 01 Sep	Delta
28 Aug - 13 Sep	Air Canada
11 Aug - 11 Sep	Air Canada
07 Aug - 04 Sep	jetBlue

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

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 August from $484

Return flights