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

Return flights

21 Sep - 07 Oct	Frontier Airlines
25 Sep - 09 Oct	Spirit Airlines
30 Sep - 25 Oct	Spirit Airlines
27 Sep - 24 Oct	Spirit Airlines
21 Sep - 11 Oct	Frontier Airlines
23 Sep - 30 Sep	Spirit Airlines
28 Sep - 18 Oct	Frontier Airlines
27 Sep - 18 Oct	Frontier Airlines
20 Sep - 11 Oct	Frontier Airlines
22 Sep - 18 Oct	Frontier Airlines
25 Sep - 18 Oct	Spirit Airlines

Also check the deals for one-way flights from Austin 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 Austin to Frankfurt in September from $781

Return flights