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

Return flights

30 Jul - 28 Aug	Aer Lingus
08 Jul - 29 Aug	Aer Lingus
30 Jul - 27 Aug	Delta
28 Jul - 13 Aug	Aer Lingus
30 Jul - 28 Aug	British Airways	direct
28 Jul - 11 Aug	Air Canada
30 Jul - 27 Aug	British Airways	direct
21 Jul - 11 Aug	Air Canada
28 Jul - 07 Aug	Air Canada
28 Jul - 12 Aug	Air Canada
16 Jul - 23 Jul	Air Canada
15 Jul - 22 Jul	Air Canada
14 Jul - 21 Jul	Air Canada
16 Jul - 21 Jul	Air Canada
13 Jul - 22 Jul	Air Canada
15 Jul - 21 Jul	Air Canada
21 Jul - 30 Jul	Delta
22 Jul - 30 Jul	Delta
14 Jul - 24 Jul	Air Canada
15 Jul - 22 Jul	American Airlines	direct

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 $474

Return flights