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

Return flights

03 Dec - 14 Dec	TAP
03 Dec - 13 Dec	TAP
29 Dec - 21 Jan	Scandinavian Airlines
13 Dec - 17 Jan	Aer Lingus
26 Dec - 17 Jan	British Airways
18 Dec - 25 Dec	Scandinavian Airlines
24 Dec - 31 Dec	Scandinavian Airlines
25 Dec - 01 Jan	Icelandair
14 Dec - 19 Dec	TAP
08 Dec - 03 Jan	TAP
18 Dec - 04 Jan	Scandinavian Airlines
26 Dec - 17 Jan	Brussels Airlines	direct
20 Dec - 29 Dec	Icelandair
25 Dec - 01 Jan	United	direct
18 Dec - 25 Dec	United	direct
08 Dec - 03 Jan	United	direct
20 Dec - 01 Jan	Icelandair
23 Dec - 30 Dec	Icelandair
14 Dec - 19 Dec	Brussels Airlines	direct
24 Dec - 31 Dec	Lufthansa	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 $477

Return flights