So called for its nearness to the old salterns of Piombino, the Torre del Sale is situated on the swampy plain between the promontory of Piombino and the hills of Campiglia Marittima. Cited in writing as of 1094, the salterns produced a great quantity of salt that satisfied local needs and was also exported: the principal markets were Florence and Siena. It was also necessary to preserve the fish from the nearby fishponds.

Known as the "Casa del Sale" (salt house) until the mid 17th century, the Tower stood on the tombolo separating the swamp from the sea in a location with unhealthy conditions, which began to improve only after the reclamation started by the Lorraines during the first half of the following century. In this period, the old "Salt House" was transformed into a veritable fortalice that was also used as a barracks and had a stable, and a hospital. In the early 19th century, an underground cistern was built inside the Fort, while a bastion with a cannon in the forecourt was built on the side facing the sea. In 1830, a tower was built to house the administration of the new reclamation works.

In 1847, the Torre del Sale was disarmed, along with many other fortalices. The upper floors of the building were used until 1960 by the Guardia di Finanza as housing and offices; works to adapt it to the new conditions modified its interior layout. The Torre del Sale complex is concerned by a study commissioned by the Commune of Piombino for the Detailed Plan of the territorial park of the eastern coast and scrublands.