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

Return flights

01 Dec - 11 Dec	ITA Airways
04 Dec - 22 Jan	British Airways
04 Dec - 18 Dec	KLM
04 Dec - 23 Dec	KLM
04 Dec - 16 Dec	KLM
04 Dec - 17 Dec	KLM
04 Dec - 08 Dec	KLM
04 Dec - 11 Dec	KLM
01 Dec - 18 Dec	KLM
01 Dec - 23 Dec	KLM
01 Dec - 16 Dec	KLM
01 Dec - 30 Jan	KLM
06 Dec - 30 Jan	KLM
10 Dec - 18 Jan	KLM
31 Dec - 21 Jan	KLM
10 Dec - 22 Jan	KLM
02 Dec - 28 Jan	SWISS
02 Dec - 29 Jan	SWISS
03 Dec - 29 Jan	SWISS
09 Dec - 22 Jan	KLM

Also check the deals for one-way flights from London to Bangkok 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 Bangkok in December from $847

Return flights