Practical gotchas

Cyrillic vs Latin signage

Major towns, highways, and tourist sites usually have bilingual signs (Bulgarian Cyrillic and Latin transliteration).
Rural roads and small villages often have only Cyrillic, especially side-road markers and bus timetables.
Common issue: Place-name transliteration varies ("Sozopol" vs "Sozopol", "Kovachevitsa" vs "Kovachevica"). Store both Cyrillic and Latin names, and use fuzzy-matching where possible.
For bus stations, destination boards are often Cyrillic-only; travelers must recognize the Bulgarian spelling (e.g., Банско for Bansko).

Highways and cities: 4G/5G coverage is generally good.
Mountains (Rila, Pirin, Stara Planina, Rhodopes): Many valleys and ridge sections have no signal across all operators; huts like Ribni Ezera or inner Pirin may have very weak or no coverage.
Coastal Strandzha and border areas: Patches of poor coverage; sometimes roaming into Turkish networks near Rezovo/Sinemorets.
Practical implication: Don't rely on live navigation or cloud-only apps in the mountains; pre-download maps and offline data before setting out.

Cities and resort towns: ATMs widespread; Visa/MasterCard widely accepted in hotels, larger restaurants, and supermarkets.
Mountain villages and huts: Villages like Kovachevitsa, Dolen, and Brashlyan often have no ATM; nearest in regional center (Gotse Delchev, Smolyan, etc.). Huts almost always cash-only; sometimes they accept only Bulgarian lev, not euro.
Cards: Visa and MasterCard accepted more than Maestro; American Express is rare.
Itinerary rule: For any multi-day trek with huts, prompt travelers to withdraw enough cash in the last major town, and treat remote destinations as "cash-only zone."

Trains: Bulgarian trains can be inexpensive but delays are common; treat connections via train with a 30-60 minute buffer.
Buses: More reliable for timing, but tickets are often sold in cash at station windows or onboard; online booking is patchy outside major intercity routes.
Language: English is widely spoken in tourist hubs, less so in rural areas; using Google Translate or similar is strongly recommended for hut phone calls and bus info.