AirHint found the following cheapest return flights from Boston (BOS) to Sofia (SOF) in December 2025 (see full year).

Return flights

03 Dec - 11 Dec	Air Canada
08 Dec - 15 Dec	Air Canada
10 Dec - 17 Dec	Air Canada
02 Dec - 16 Dec	Air Canada
02 Dec - 09 Dec	SWISS
09 Dec - 18 Dec	Air Canada
09 Dec - 16 Dec	Air Canada
09 Dec - 23 Dec	Air Canada
14 Dec - 23 Dec	Austrian Airlines
10 Dec - 06 Jan	Air Canada
08 Dec - 21 Dec	Air Canada
25 Dec - 15 Jan	Air Canada
24 Dec - 07 Jan	Air Canada
25 Dec - 08 Jan	Air Canada
23 Dec - 06 Jan	Austrian Airlines
26 Dec - 04 Jan	Austrian Airlines
24 Dec - 03 Jan	Lufthansa
22 Dec - 05 Jan	SWISS

Also check the deals for one-way flights from Boston to Sofia 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 Boston to Sofia in December from $364

Return flights