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

Return flights

28 Dec - 15 Jan	TAP
10 Dec - 14 Dec	TAP
07 Dec - 14 Dec	TAP
07 Dec - 18 Dec	TAP
03 Dec - 09 Dec	TAP
03 Dec - 10 Dec	TAP
07 Dec - 13 Dec	TAP
03 Dec - 17 Dec	Aer Lingus
03 Dec - 08 Dec	Air Canada
29 Dec - 09 Jan	Aer Lingus
05 Dec - 07 Dec	Scandinavian Airlines
12 Dec - 11 Jan	Icelandair
02 Dec - 09 Dec	Aer Lingus
31 Dec - 09 Jan	Aer Lingus
30 Dec - 09 Jan	Aer Lingus
30 Dec - 14 Jan	Aer Lingus
30 Dec - 08 Jan	Lufthansa
12 Dec - 10 Jan	Icelandair
11 Dec - 10 Jan	Icelandair
29 Dec - 11 Jan	Aer Lingus

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 360€

Return flights