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

Return flights

07 Oct - 21 Oct	Air Canada
04 Oct - 11 Oct	Turkish Airlines
06 Oct - 18 Oct	Turkish Airlines
10 Oct - 24 Oct	Air Canada
01 Oct - 08 Oct	United
29 Oct - 09 Nov	Air Canada
22 Oct - 29 Oct	United
07 Oct - 14 Oct	United
17 Oct - 24 Oct	United
12 Oct - 19 Oct	United
27 Oct - 03 Nov	United

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

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 October from $533

Return flights