The patron of Massa Marittima is Saint Cerbonius, celebrated on 10 October with a medieval costume procession from Piazza Cavour to Piazza Garibaldi, closing with mass and the liturgical ceremony of the candle and the census in the cathedral.
The town is also known for the Balestro del Girifalco, a historic crossbow contest held twice a year in Piazza Garibaldi since the 14th century.