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

Return flights

05 Dec - 07 Dec	Icelandair
01 Dec - 12 Dec	Icelandair
02 Dec - 09 Dec	Icelandair
03 Dec - 08 Dec	Icelandair
04 Dec - 08 Dec	Icelandair
03 Dec - 09 Dec	Icelandair
02 Dec - 07 Dec	Icelandair
03 Dec - 07 Dec	Icelandair
01 Dec - 14 Dec	Icelandair
05 Dec - 12 Dec	Icelandair
15 Dec - 09 Jan	Spirit Airlines
31 Dec - 14 Jan	Icelandair
29 Dec - 14 Jan	Icelandair
29 Dec - 12 Jan	Icelandair
30 Dec - 14 Jan	Icelandair
15 Dec - 11 Jan	Spirit Airlines
15 Dec - 10 Jan	Spirit Airlines
13 Dec - 10 Jan	Spirit Airlines
28 Dec - 14 Jan	Icelandair
31 Dec - 10 Jan	TAP

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 $493

Return flights