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

Return flights

09 Sep - 11 Sep	Lufthansa
07 Sep - 09 Sep	Lufthansa
13 Sep - 16 Sep	Air Canada
02 Sep - 05 Sep	SWISS
06 Sep - 09 Sep	SWISS
01 Sep - 08 Sep	Lufthansa
03 Sep - 10 Sep	Lufthansa
21 Sep - 30 Sep	Lufthansa
08 Sep - 15 Sep	Lufthansa
07 Sep - 15 Sep	Lufthansa
29 Sep - 06 Oct	Lufthansa
26 Sep - 12 Oct	Lufthansa
20 Sep - 11 Oct	Aer Lingus
28 Sep - 28 Oct	Aer Lingus
19 Sep - 11 Oct	Aer Lingus
30 Sep - 05 Oct	Aer Lingus
13 Sep - 04 Oct	Aer Lingus
27 Sep - 18 Oct	Aer Lingus
22 Sep - 03 Oct	Aer Lingus
29 Sep - 25 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 304€

Return flights