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

Return flights

01 Dec - 31 Dec	Scandinavian Airlines
31 Dec - 14 Jan	Aer Lingus
28 Dec - 11 Jan	Aer Lingus
03 Dec - 10 Dec	United
08 Dec - 15 Dec	United	direct
28 Dec - 11 Jan	United	direct
29 Dec - 04 Jan	Scandinavian Airlines
13 Dec - 20 Dec	United
19 Dec - 25 Dec	British Airways
19 Dec - 24 Dec	British Airways
19 Dec - 26 Dec	Aer Lingus
31 Dec - 14 Jan	Brussels Airlines	direct
22 Dec - 03 Jan	Aer Lingus
18 Dec - 25 Dec	United	direct
29 Dec - 04 Jan	United	direct
28 Dec - 04 Jan	United	direct
20 Dec - 03 Jan	Aer Lingus
19 Dec - 24 Dec	United	direct
19 Dec - 25 Dec	United	direct
22 Dec - 03 Jan	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 $491

Return flights