Effective from 29 January 2021, all arrivals to Bulgaria, no matter their point of departure, must show documentary evidence of a negative PCR test taken in the 72 hours before departure.
Bulgarian government advice is that Bulgarian citizens and foreign nationals with valid residence permits, as well as their family members, who do not present such a document must self-isolate for 10 days.
Exemptions include: bus and lorry drivers, crews of vessels and aircraft, border workers...