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Is there a railroad, bus or bus service to Varna, Bulgaria to Athens, Greece?
Goal of a week in Bulgaria, but you must go to Athens for a wedding – which is the simplest and the way a good value to do?
Hello, Yes, there are bus services to go from Varna to Athens. First you will need to travel to Sofia. If you go to the bus station in Varna, they sell Tickets go directly to Sofia with the national bus service. Tickets cost about 14 up and takes 4-5 hours. Sofia direct bus to go to Athens with Etap or group or Kamilcoach Biomet. Sofia's journey takes 15 hours and should cost about 60-80 Euros. I made the trip and it's not too bad, but be sure to take Euros with you when you cross the border. 
Good luck, Kristen
Balkan map / Greater Greece, Bulgaria, Serbia and Croatia!