Fort Nepean, Coastal defense fort at Point Nepean, Victoria, Australia

Fort Nepean is a coastal defense installation at Point Nepean that guards the entrance to Port Phillip Bay. The structure comprises underground tunnels, gun emplacements, and concrete bunkers connected by steep staircases, creating a layered military complex built directly into the landscape.

Fort Nepean was built from 1873 as part of the defences recommended by Sir William Jervois and Colonel Russel Coight, and gun batteries were installed in 1886. On 5 August 1914 its B1 gun fired across the bow of the German ship SS Pfalz, and at 1:30 am on 4 September 1939 its A1 gun fired at the freighter SS Woniora. These were the only shots fired in anger by any Port Phillip battery.

The fort's nickname, "Victoria's Gibraltar", dates from the 1890s, when its scale was compared to the Mediterranean rock. The barracks housed a company of the Royal Victoria Volunteer Artillery Regiment, raised to garrison the site. The two Mk VII gun barrels that fired in anger were recovered from a Port Wakefield proving ground and a Brooklyn scrapyard in the 1960s and brought back to the fort.

Sturdy footwear and good footing are essential as the site involves many steep staircases and tight concrete passages throughout. The grounds are largely exposed, so weather protection matters and allowing plenty of time to explore is wise, since the maze of underground rooms can be disorienting.

The two Mk VII gun barrels that fired the opening shots of both World Wars were scrapped after 1945, then retrieved in the 1960s from the Port Wakefield proving ground and a Brooklyn scrapyard and returned to the fort. The 1914 shot was fired by the B1 gun across the bow of the German ship SS Pfalz.