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

Return flights

03 Dec - 07 Dec	TAP
10 Dec - 14 Dec	TAP
29 Dec - 11 Jan	Scandinavian Airlines
15 Dec - 10 Jan	Aer Lingus
14 Dec - 10 Jan	Aer Lingus
12 Dec - 22 Dec	SWISS
16 Dec - 11 Jan	Aer Lingus
16 Dec - 10 Jan	Aer Lingus
02 Dec - 27 Dec	Aer Lingus
11 Dec - 17 Dec	British Airways
28 Dec - 11 Jan	British Airways
26 Dec - 17 Jan	British Airways
18 Dec - 25 Dec	Scandinavian Airlines
12 Dec - 22 Dec	United	direct
25 Dec - 29 Dec	Turkish Airlines
17 Dec - 11 Jan	Scandinavian Airlines
15 Dec - 10 Jan	United	direct
16 Dec - 10 Jan	United	direct
03 Dec - 07 Dec	United	direct
02 Dec - 27 Dec	United	direct

Also check the deals for one-way flights from Washington 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 Washington to Brussels in December from 424€

Return flights