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

Return flights

19 Aug - 29 Aug	Lufthansa
19 Aug - 25 Aug	Air Canada
13 Aug - 20 Aug	Lufthansa
18 Aug - 27 Aug	Finnair
04 Aug - 18 Aug	Icelandair
23 Aug - 31 Aug	Icelandair
22 Aug - 09 Sep	Icelandair
11 Aug - 18 Aug	Icelandair
12 Aug - 12 Sep	SWISS
13 Aug - 12 Sep	SWISS
12 Aug - 05 Sep	SWISS
08 Aug - 26 Aug	Austrian Airlines
12 Aug - 18 Aug	Icelandair
04 Aug - 26 Aug	SWISS
19 Aug - 04 Sep	SWISS
20 Aug - 18 Sep	Delta
20 Aug - 10 Sep	Virgin Atlantic
26 Aug - 02 Sep	British Airways	direct
11 Aug - 12 Sep	Delta
13 Aug - 09 Sep	KLM

Also check the deals for one-way flights from Chicago 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 Chicago to London in August from 402€

Return flights