Currently there are no direct flights Sofia to Slovakia.

Flights Sofia to Slovakia with 1 stopover:

Flights via Moscow Sheremetievo (SVO), Moscow, Russia
From Sofia (SOF), Bulgaria with Aeroflot
OR
From Sofia (SOF), Bulgaria with Aerosvit
Transfer at Moscow Sheremetievo (SVO), Moscow, Russia Then on to Bratislava (BTS), Bratislava, Slovakia with Aeroflot