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

Return flights

24 Dec - 07 Jan	Delta
14 Dec - 21 Dec	Delta
23 Dec - 07 Jan	Delta
22 Dec - 07 Jan	Delta
24 Dec - 06 Jan	Delta
08 Dec - 05 Jan	Delta
23 Dec - 06 Jan	Delta
22 Dec - 29 Dec	Delta
27 Dec - 06 Jan	Air France
28 Dec - 05 Jan	Virgin Atlantic
24 Dec - 05 Jan	Virgin Atlantic
06 Dec - 03 Jan	Delta

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 $720

Return flights