AirHint found the following cheapest return flights from London (LCY) to Boston (BOS) in August 2025 (see full year).

Return flights

27 Aug - 10 Sep	KLM
20 Aug - 25 Aug	KLM
18 Aug - 25 Aug	Delta
27 Aug - 02 Sep	KLM
26 Aug - 04 Sep	KLM
27 Aug - 03 Sep	KLM
26 Aug - 02 Sep	KLM
25 Aug - 02 Sep	Delta
12 Aug - 25 Aug	KLM
11 Aug - 21 Aug	Delta
12 Aug - 19 Aug	KLM
12 Aug - 18 Aug	Virgin Atlantic
11 Aug - 19 Aug	KLM
11 Aug - 25 Aug	Delta
11 Aug - 18 Aug	KLM
13 Aug - 03 Sep	Virgin Atlantic
07 Aug - 09 Sep	Lufthansa
21 Aug - 30 Sep	KLM
14 Aug - 21 Aug	SWISS
27 Aug - 11 Sep	SWISS

Also check the deals for one-way flights from London to Boston 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 London to Boston in August from $563

Return flights