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

Return flights

13 Dec - 08 Jan	Frontier Airlines
01 Dec - 10 Dec	Frontier Airlines
21 Dec - 28 Dec	Frontier Airlines
31 Dec - 09 Jan	Lufthansa
20 Dec - 27 Dec	Frontier Airlines
19 Dec - 29 Dec	Frontier Airlines
29 Dec - 03 Jan	Frontier Airlines
15 Dec - 02 Jan	Frontier Airlines
23 Dec - 02 Jan	Frontier Airlines
31 Dec - 05 Jan	Lufthansa
26 Dec - 02 Jan	Southern Airways Express

Also check the deals for one-way flights from St. Louis to London 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 London in December from $619

Return flights