AirHint found the following cheapest return flights from London (LCY) to Brussels (BRU) in December 2025 (see full year).

Return flights

26 Dec - 29 Dec	Lufthansa
05 Dec - 08 Dec	SWISS
12 Dec - 15 Dec	SWISS
13 Dec - 15 Dec	SWISS
01 Dec - 04 Dec	SWISS
17 Dec - 17 Jan	KLM
24 Dec - 31 Dec	KLM
24 Dec - 02 Jan	KLM
24 Dec - 03 Jan	KLM
23 Dec - 03 Jan	KLM
15 Dec - 18 Dec	KLM
11 Dec - 15 Dec	KLM
15 Dec - 19 Dec	KLM
19 Dec - 21 Dec	KLM
31 Dec - 02 Jan	SWISS

Also check the deals for one-way flights from London to Brussels 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 London to Brussels in December from $259

Return flights