Fort São Sebastião, Portuguese fortress on Island of Mozambique, Mozambique.

Fort São Sebastião is a rectangular fortress with thick coral walls at the northern end of Stone Town on Mozambique Island. Built by the Portuguese from 1558, it has a central courtyard surrounded by barracks, storage rooms and chapels, with cannons still mounted on the ramparts.

Italian architect Giovanni Battista Cairati designed this military stronghold in 1558, though construction took fifty years to complete. Portugal built the fort to control important trade routes eastward and establish dominance along the African coast.

The fort blends European military design with local building methods, using coral stone quarried nearby for its walls. Visitors walking through can see how two architectural traditions came together in this stone structure.

Guided tours provide access to interior sections including former barracks and storage areas with preserved cannons on display. Visitors should wear comfortable shoes since exploring the stone structure involves uneven flooring and narrow stairways.

The fort has housed the Faculty of Social and Human Sciences of Lúrio University since 2017, so students attend classes inside its walls. The Zamani Project of the University of Cape Town scanned the whole structure in 3D in 2013, producing a digital record for research and restoration.