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

Return flights

25 Aug - 06 Sep	Austrian Airlines
31 Aug - 21 Sep	United
30 Aug - 09 Sep	TAP
29 Aug - 11 Sep	SWISS
19 Aug - 15 Sep	Delta
31 Aug - 12 Sep	Air Canada
20 Aug - 10 Sep	KLM
26 Aug - 09 Sep	Delta
29 Aug - 02 Sep	SWISS
29 Aug - 05 Sep	SWISS
19 Aug - 25 Aug	Delta
20 Aug - 25 Aug	Delta
18 Aug - 25 Aug	Delta
18 Aug - 27 Aug	Delta
18 Aug - 28 Aug	Delta
20 Aug - 26 Aug	Delta
19 Aug - 26 Aug	KLM
20 Aug - 27 Aug	KLM
04 Aug - 12 Aug	Delta
04 Aug - 13 Aug	Delta

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 $446

Return flights