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

Return flights

08 Sep - 10 Sep	United
05 Sep - 08 Sep	Scandinavian Airlines
22 Sep - 29 Sep	Lufthansa
05 Sep - 09 Sep	Lufthansa
01 Sep - 06 Sep	Lufthansa
08 Sep - 15 Sep	Lufthansa
01 Sep - 08 Sep	Lufthansa
09 Sep - 25 Sep	Lufthansa
10 Sep - 24 Sep	Lufthansa
13 Sep - 18 Sep	Lufthansa
27 Sep - 11 Oct	Aer Lingus
29 Sep - 03 Oct	Aer Lingus
25 Sep - 02 Oct	Aer Lingus
25 Sep - 04 Oct	Aer Lingus
25 Sep - 22 Oct	Aer Lingus
24 Sep - 01 Oct	United
24 Sep - 05 Oct	SWISS
23 Sep - 02 Oct	SWISS
30 Sep - 08 Oct	United
17 Sep - 08 Oct	Aer Lingus

Also check the deals for one-way flights from Boston to London in September.

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 Boston to London in September from 331€

Return flights