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

Return flights

26 Sep - 05 Oct	Iberia
04 Sep - 08 Sep	Icelandair
23 Sep - 30 Sep	Icelandair
02 Sep - 09 Sep	Icelandair
10 Sep - 14 Sep	Icelandair
11 Sep - 18 Sep	Icelandair
14 Sep - 21 Sep	Icelandair
29 Sep - 06 Oct	Icelandair
05 Sep - 12 Sep	Icelandair
17 Sep - 05 Oct	TAP
08 Sep - 15 Sep	Icelandair
04 Sep - 08 Sep	Condor	direct
12 Sep - 14 Sep	Condor	direct
26 Sep - 03 Oct	Iberia
16 Sep - 01 Oct	Lufthansa	direct
22 Sep - 08 Oct	Lufthansa	direct
26 Sep - 03 Oct	Lufthansa	direct
29 Sep - 06 Oct	Lufthansa	direct
26 Sep - 05 Oct	Lufthansa	direct

Also check the deals for one-way flights from Boston to Frankfurt 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 Frankfurt in September from 440€

Return flights