It was built between 1879 and 1883 by the British on high ground at the shoreward end of Delimara Point, above il-Ħofra-ż-Żgħira.

It was part of a chain of fortifications intended to protect Marsaxlokk Harbour, along with Fort Delimara seaward along Delimara point, the north arm of Marsaxlokk Bay, Fort San Lucian on Kbira point in the middle of the bay, Fort Benghisa on Bengħisa Point, and the Pinto and Ferretti batteries on the shores of the bay.

Approximately 300 metres north of Fort Tas-Silġ is the Saint Paul's Battery, a much smaller polygonal style fortification, that is in much worse condition.

The first stone of Fort Tas-Silġ was laid down in 1879 after a suggestion by British military engineers, and it was completed in 1883.

The fort is surrounded by a ditch, and the entrance was protected with gun ports on one side and a bridge leading to the door.