The cheapest flight to Lisbon you can get by boooking 45 days before departure.
The most popular airlines on the route Sofia - Lisbon: Lufthansa (LH), Bulgaria Air (FB), KLM (KL).
The cheapest flights you can book on the route Sofia Airport (SOF) - Portela (LIS).
Direct flights last about 4h 10min.
Direct flights available 2 days a week - Monday, Thursday.
Direct flights: Bulgaria Air (FB).