 Castro later decayed, and the bishop's residence was transferred to Bono.On 8 December 1503, the territory of Castro and that of two other dioceses were combined to form the new diocese of Alghero (now Alghero-Bosa).Today what was the territory of Castro is part of that of the diocese of Ozieri

Castro itself, no longer a residential bishopric, is listed by the Catholic Church as a titular see since its nominal restoration as a Latin Catholic titular bishopric in 1968, initially simply as Castro, since 1976 as Castro di Sardegna, avoiding confusion with sees named Castro in Lazio and in Puglia.