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

Return flights

08 Oct - 15 Oct	Turkish Airlines
17 Oct - 31 Oct	Turkish Airlines
05 Oct - 22 Oct	Turkish Airlines
05 Oct - 23 Oct	Turkish Airlines
20 Oct - 03 Nov	Turkish Airlines
05 Oct - 21 Oct	Turkish Airlines
20 Oct - 15 Nov	Turkish Airlines
05 Oct - 20 Oct	Turkish Airlines
05 Oct - 24 Oct	Frontier Airlines
05 Oct - 25 Oct	TAP
18 Oct - 20 Oct	Turkish Airlines
28 Oct - 04 Nov	United
13 Oct - 20 Oct	Turkish Airlines
31 Oct - 07 Nov	United
25 Oct - 01 Nov	United
04 Oct - 01 Nov	Spirit Airlines

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.

Book a cheap hotel in Sofia

Cheap car rent in Sofia

Cheapest return flights from Chicago to Sofia in October from $504

Return flights