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

Return flights

30 Dec - 30 Jan	Frontier Airlines
13 Dec - 29 Dec	Frontier Airlines
12 Dec - 17 Dec	Frontier Airlines
18 Dec - 10 Jan	Frontier Airlines
12 Dec - 21 Dec	Frontier Airlines
13 Dec - 21 Dec	Frontier Airlines
13 Dec - 02 Jan	Frontier Airlines
15 Dec - 02 Jan	Frontier Airlines
25 Dec - 01 Jan	Frontier Airlines
23 Dec - 02 Jan	Frontier Airlines
26 Dec - 02 Jan	Frontier Airlines
19 Dec - 06 Jan	Frontier Airlines

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 713€

Return flights