An ICAO Article 83bis Agreement defines the division of regulatory oversight responsibilities between San Marino, as the State of Registry, and a foreign civil aviation authority, as State of the Operator, in relation to the operation of San Marino registered aircraft.
This means that aircraft registered in San Marino can be operated for commercial purposes by a foreign Aircraft Operator Certificate (AOC) holder.
Currently, the Republic of San Marino has an Article 83bis agreement with:
Republic of Lebanon
Kingdom of Saudi Arabia