SA.CO.I is a 200 kV HVDC submarine interconnection of about 120 km between Tuscany and Corsica and across the Strait of Bonifacio, constructed by the former Pirelli Cavi in 1965; with two parallel cables this equates to roughly 242 km of manufactured subsea cable used for the Sardinia–Corsica–Italy link.
Pirelli Cavi designed, manufactured and installed the original SA.CO.I high-voltage direct current submarine cable system linking Sardinia, Corsica and mainland Italy, which forms the subsea cable backbone later operated as the SACOI2 interconnection. In the mid‑1960s the company delivered a 200 kV HVDC submarine link of around 120 km route length, laid between Tuscany and Corsica and across the Strait of Bonifacio. With two parallel cables along the route, this corresponds to roughly 242 km of manufactured HVDC subsea cable. The turnkey scope covered engineering of the cable system, production of the submarine cables and their installation and commissioning along the full undersea route, providing the primary transmission path between the three territories.