2400 km along the Bulgarian borders (routes EuroVelo13 and EuroVelo 6) and along the Black Sea coast from Rezovo to the Danube Delta for about a month.
EuroVelo 13 – Chatama (Dospat) – Rezovo
Coastal route – Rezovo – Tulcea
EuroVelo 6 – Danube Delta – Bregovo
The Wikiloc Travel Tracks