The cheapest flight to Sofia you can get by boooking 25 days before departure.
The most popular airlines on the route Stockholm - Sofia: Ryanair (FR), Air Serbia (JU), LOT (LO).
The cheapest flights you can book on the route Skavsta (NYO) - Sofia Airport (SOF).
Direct flights last about 2h 50min.
Direct flights available 2 days a week - Wednesday, Sunday.
Direct flights: Ryanair (FR).