Sydney Harbour defences

Sydney Harbour defences form a defensive network around the harbor, including batteries, gun emplacements, and underground tunnels carved into coastal sandstone cliffs. The structures spread across several locations within Sydney Harbour National Park.

Dawes Point Battery, the first fortification, was built in 1791 to guard the colony against Spanish warships and remained in use until the 1960s. The defensive network expanded over decades as new threats emerged.

These fortifications show colonial military design built partly by convict labor, telling how early settlers feared invasion and wanted to protect their harbor. The structures reflect anxieties of a young settlement far from home.

Several fortification sites are accessible through Sydney Harbour National Park with views over the water and insights into defense history. Wear sturdy shoes since paths are uneven and the rocks can be slippery.

During World War II an anti-submarine boom net was installed that successfully stopped Japanese midget submarines from entering the harbor in 1942. This visible relic shows how critical the harbor was to Australia's defense.

Location: New South Wales

GPS coordinates: -33.83850,151.25600

Latest update: December 10, 2025 20:07