The Investiture of the Captains Regent is a significant bi-annual event celebrated in San Marino. This holiday marks the inauguration of two new Captains Regent, who serve as the heads of state for the Republic of San Marino. The Captains Regent are nominated by the country's Grand and General Council and their investiture ceremony occurs twice a year on the 1st of April and 1st of October.

The celebration is characterized by a grand ceremony filled with local traditions and rituals. It commences with the presence of the outgoing captains who hand over the reins of leadership to the incoming captains. All the proceedings during the day are etched in history to ensure that they become a part of the rich cultural heritage of San Marino. The streets are typically filled with processions and the sounds of the national anthem fill the air, signifying the changing of the government.

Apart from the grand official event, Investiture of the Captains Regent also entails a celebratory vibe among the natives of San Marino. Various cultural performances, feasts, and other communal activities take place. The day holds great importance as it has been a tradition since 1243, making it one of the oldest existing forms of government. It symbolizes the democratic values upheld by the microstate of San Marino and emphasizes the peaceful transition of power.