AirHint found the following cheapest return flights from Chicago (ORD) to Sofia (SOF) in August 2025 (see full year).

Return flights

31 Aug - 19 Sep	Lufthansa
18 Aug - 03 Sep	SWISS
19 Aug - 05 Sep	Lufthansa
13 Aug - 27 Aug	SWISS
18 Aug - 04 Sep	SWISS
20 Aug - 27 Aug	United
26 Aug - 02 Sep	United
25 Aug - 10 Sep	Turkish Airlines
21 Aug - 04 Sep	Turkish Airlines
28 Aug - 04 Sep	United
14 Aug - 02 Sep	Turkish Airlines
16 Aug - 02 Sep	Lufthansa
13 Aug - 20 Aug	SWISS
14 Aug - 21 Aug	United
03 Aug - 24 Aug	ITA Airways
22 Aug - 29 Aug	United
15 Aug - 20 Aug	SWISS
04 Aug - 18 Aug	Icelandair
04 Aug - 24 Aug	TAP
15 Aug - 22 Aug	SWISS

Also check the deals for one-way flights from Chicago to Sofia in August.

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 Chicago to Sofia in August from 478€

Return flights