Port Phillip (Kulin: Naarm), also commonly referred to as Port Phillip Bay, is a horsehead-shaped bay on the central coastline of southern Victoria, Australia. The bay opens into the Bass Strait through a narrow channel known as The Rip, and is surrounded mostly by metropolitan Greater Melbourne in its main eastern portion north of the Mornington Peninsula, and the city of Greater Geelong in the much smaller western portion north of the Bellarine Peninsula. Geographically, the bay covers 1,930 square kilometres (480,000 acres) and the shore stretches roughly 264 km (164 mi), with the volume of water around 25 cubic kilometres (6.0 cu mi). Most of the bay is navigable, although it is extremely shallow for its size — the deepest portion is only 24 metres (79 ft) and half the bay is shallowe