It was built between 1872 and 1878 by the British between the villages of San Leonardo and Żonqor above the shore east of the Grand Harbour.

Fort Leonardo was built between 1872 and 1878 by the British, as part of a programme of improvements to Malta's fortifications recommended in Colonel Jervois' Report of 1866.

A modern construction, possibly a reservoir, alongside the shoreward side of the fort detracts from its original appearance, and the approach to the main gate has been mined for rubble and is substantially damaged.

In 2011, a 60-metre high communications tower of the telecommunications company GO was approved to be built on the glacis of the fort.

Din l-Art Ħelwa said that the fort should be restored, but its military context should not be lost as was done with Cambridge Battery on Tigné Point.