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

Return flights

18 Sep - 05 Oct	Icelandair
10 Sep - 17 Sep	Ryanair
15 Sep - 07 Oct	Scandinavian Airlines
01 Sep - 15 Sep	Icelandair
18 Sep - 30 Sep	Icelandair
21 Sep - 11 Oct	Icelandair
25 Sep - 13 Oct	Icelandair
09 Sep - 23 Sep	Aer Lingus
07 Sep - 27 Sep	Aer Lingus
27 Sep - 05 Oct	American Airlines
12 Sep - 28 Sep	Iberia
03 Sep - 17 Sep	Iberia
04 Sep - 19 Sep	Iberia
14 Sep - 26 Sep	Iberia
12 Sep - 21 Sep	Iberia
26 Sep - 03 Oct	Iberia
08 Sep - 06 Oct	Ryanair
22 Sep - 02 Oct	Icelandair
27 Sep - 18 Oct	British Airways
18 Sep - 05 Oct	Condor	direct

Also check the deals for one-way flights from Frankfurt to Boston 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 Frankfurt to Boston in September from $514

Return flights