This massive fortress occupies the promontory at the south entrance of Grand Harbour, opposite Fort St. Elmo. It was designed by the famous military engineer Maurizio Valperga, and was built at the expense of the Italian Knight Giovanni Francesco Ricasoli, whose name it bears to this day. Grand Master Nicola Cottoner endowed the fort and built the chapel of St. Nicholas in the courtyard.

The chapel's altarpiece was painted by Matia Preti. In 1698, further additions were added by Grand Master Perellos. Fort Ricasoli, with its seven sturdy bastions, its ravelins, demibastions and the extensive curtain-walls, was considered an impregnable stronghold. In the 18th century, the knights set up a gallows on Ricasoli Point where galley-slaves, who tried to escape from their posts, were hanged The gallows served as a stem warning to crews entering the harbour of the destiny awaiting those who abandoned their place in the galleys.

During the 19th century, the British constructed several casemates for heavy guns, gun turrets and emplacements, and barracks for the garrison. up to 1870, the fort was manned by 700 officers and men. It had more than 100 guns mounted on batteries facing the sea.

After 1872, many of the guns were replaced by heavier ones, including four mounted in casemates behind steel shields. The fort played an important role during World War II. It was attacked several times by German dive bombers. The Gunner's House, and the elegant baroque gate with its fine twisted columns, received direct hits and were totally destroyed; the gateway was eventually rebuilt.

After the war, Fort Ricasoli was used for several years as naval barracks. Today, the fort still stands sentinel at the harbour entrance, but its guns are silent and its garrisons have disappeared. There are plans to turn Fort Ricasoli into an environmental park.