The Donato Bastion, named after the Capitano, Crete’s military chief, Natal Donato, is simpler and smaller compared to the Tiepolo Bastion. It has two fronts, one to the south and one to the east, and its redent, which is well-preserved, extends into the sea. At the top of the redent, there is a circular watch tower roofed with vault. The parapet with the battlements on the exterior, on the bastion's flank, and the battlements on the redent near the watch tower are additions from the Cretan War era. During the same period, two open cannon ports are constructed.

From the early years of the Leper Colony, the square of the Donato bastion is transformed into a cemetery. Subsequently, when the space becomes insufficient, the open cannon ports are removed, and graves made of concrete are constructed. A small ossuary is also formed on the Donato bastion's northern side.