AirHint found the following cheapest return flights from Helsinki (HEL) to Sofia (SOF) in September 2025 (see full year).

Return flights

09 Sep - 29 Sep	Ryanair
30 Sep - 02 Oct	Ryanair
22 Sep - 28 Sep	Ryanair
10 Sep - 14 Sep	Ryanair
20 Sep - 22 Sep	Ryanair
17 Sep - 21 Sep	Ryanair
22 Sep - 30 Sep	Ryanair
25 Sep - 30 Sep	Ryanair
18 Sep - 22 Sep	Ryanair
18 Sep - 25 Sep	Ryanair
19 Sep - 22 Sep	Pegasus Airlines
09 Sep - 24 Oct	Ryanair

Also check the deals for one-way flights from Helsinki to Sofia in September.

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 Helsinki to Sofia in September from 140€

Return flights