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

Return flights

31 Dec - 14 Jan	Icelandair
30 Dec - 24 Jan	Spirit Airlines
30 Dec - 10 Jan	Aer Lingus
29 Dec - 18 Jan	SWISS
29 Dec - 10 Jan	SWISS
29 Dec - 13 Jan	Icelandair
29 Dec - 14 Jan	Aer Lingus
29 Dec - 19 Jan	SWISS
28 Dec - 13 Jan	SWISS
28 Dec - 10 Jan	SWISS
24 Dec - 29 Dec	SWISS
24 Dec - 28 Dec	SWISS
25 Dec - 30 Dec	SWISS
24 Dec - 30 Dec	Lufthansa
25 Dec - 31 Dec	SWISS
25 Dec - 28 Dec	SWISS
26 Dec - 31 Dec	Frontier Airlines

Also check the deals for one-way flights from Chicago 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 Chicago to London in December from 557€

Return flights