The gates led directly to the Old Mole which extended into the bay and provided shelter for trading vessels. The mole provided an anchoring line for the galleys. An aqueduct ran from a well to the south along the line wall to the Waterport, where it replenished a reservoir from which water for the galleys was drawn.
The British built the Line Wall Curtain in the 18th century running north–south along the shore of the bay incorporating much of the Moorish and Spanish line of fortifications along the western coast. The Waterport Gate, providing access to the town through the Line Wall from the shore south of North Bastion, was opened by the British in 1727.
The Waterport Gate became the main entrance to Gibraltar in the early days of British occupation, described by the theologian and traveller Robert Poole in 1748 as consisting ‘mainly of one street extending from Southport gate to Waterport Gate. Out of this long street run several shorter ones one of which, called the Irish-Street is of ill repute. The buildings of this town are generally mean and low, very few houses being above one story high. They are chiefly made of stone and the roof covered with Spanish tiles. The shops are small and ... are occupied by Genoese, Jews and Turks. Profane swearing and cursing is extremely common...’
After the Great Siege, the British extended North Bastion almost doubling in size. This shortened the curtain wall on the North side of the Waterport Gate to its present length.