The patron of Fonni is Saint John the Baptist, celebrated on 24 June with the feast of Santu Juvanne, which renews ancient traditions every June with great popular participation, together with the feast of Sos Martires in honour of the Madonna dei Martiri, whose shrine is among the town's most important sites.
During the feast the Palio di San Giovanni is raced: the winning jockey then represents Fonni at the Palio di Fonni, or Palio dei Comuni, held every year since 1985 at the municipal racetrack on the first Sunday of August. The town also holds the nuragic shrine of Gremanu and the Nuraghe Dronnoro.
