Forte San Giacomo, Military fort in Vado Ligure, Italy.

Forte San Giacomo is a fortification on the Ligurian coast near Vado Ligure featuring four bastions, underground storage areas, and a parade ground. The structure sits alongside Forte Santo Stefano, connected by external walls and passages that create an integrated defensive network.

The Genoese Republic built the fort between 1757 and 1759 on the ruins of the earlier Forte San Lorenzo, demolished in 1658. Field marshal Antonio Federico Flobert began work on 6 June 1757, but poor materials and water infiltration led the Senate to replace him in 1758 with French colonel and cartographer Pierre De Cotte. French soldiers under Napoleon used it during the Alpine war and first Italian campaign, 1792–1797.

The fort's name changed from San Lorenzo to San Giacomo, and its walls still link it to Forte Santo Stefano. The two works form one defensive system, joined by external walls and underground passages that visitors can trace between the structures.

The fort stands on the Capo di Vado near Vado Ligure, along the coastal road. It is linked to Forte Santo Stefano by external walls and underground passages; visitors should expect narrow corridors and wear sturdy shoes when exploring the interior.

The 1758 redesign by Pierre De Cotte addressed a fatal flaw: the fort was exposed to attacks from behind. The solution was to merge it with the older Forte Santo Stefano into one fortress, linked by external walls and underground passages that still connect the two today.