AirHint found the following cheapest return flights from St. Louis (STL) to Frankfurt (FRA) in December 2025 (see full year).

Return flights

12 Dec - 10 Jan	Frontier Airlines
24 Dec - 17 Jan	Frontier Airlines
12 Dec - 25 Dec	Frontier Airlines
17 Dec - 10 Jan	Frontier Airlines
10 Dec - 17 Dec	Lufthansa
12 Dec - 03 Jan	Frontier Airlines
08 Dec - 15 Dec	Lufthansa
11 Dec - 03 Jan	Frontier Airlines
09 Dec - 03 Jan	Frontier Airlines
31 Dec - 07 Jan	Lufthansa	direct
21 Dec - 28 Dec	Frontier Airlines
12 Dec - 21 Dec	Finnair
02 Dec - 09 Dec	Lufthansa
28 Dec - 04 Jan	Frontier Airlines
04 Dec - 11 Dec	Lufthansa
17 Dec - 24 Dec	Lufthansa	direct
15 Dec - 22 Dec	Lufthansa
06 Dec - 13 Dec	Lufthansa
25 Dec - 01 Jan	Lufthansa
29 Dec - 05 Jan	Lufthansa

Also check the deals for one-way flights from St. Louis to Frankfurt in December.

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 St. Louis to Frankfurt in December from $778

Return flights