The patron of Castelplanio is Saint Joseph, celebrated on 24 April.
Since 1977, every year between July and August, the town hosts the Sagra della crescia sul panàro, one of the longest-running festivals in the Vallesina: visitors taste crescia, a polenta flatbread cooked on the panàro, a metal disc heated on embers. The town also holds the Church of Santa Maria di Loreto and the Abbey of San Benedetto del Frondigliosi.
