Port Phillip Bay, inlet of Bass Strait on the south-central coast of Victoria, Australia, extending approximately 30 miles (50 km) north-south and 25 miles (40 km) east-west. The large metropolitan area of Melbourne, the state capital, is located at the head of the bay. Rivers emptying into the bay include the Little, Werribee, and Yarra.
The bay’s entrance, known as “the Rip” (1.75 miles [2.8 km] wide), between Points Lonsdale to the west and Nepean to the east, leads into a navigation channel 3,600 feet (1,100 metres) wide and 45 feet (14 metres) deep, with access northward to Hobsons Bay and westward to Corio Bay (the harbour of Geelong). It was visited in 1802 by Lieutenant John Murray of the Royal Navy. Murray named it Port King to honour Captain Philip Gidley King, then the governor of New South Wales, of which Victoria was then a part. It was later renamed for Captain Arthur Phillip, the first (1788–92) governor of New South Wales.
A number of settlements took form around the bay beginning in the 1830s. Among them were what would become Melbourne, Hobsons Bay, and Geelong. In the 20th century the booming ports around Port Phillip Bay made it one of the country’s largest shipping areas. The city of Port Phillip, located on the northern shore of the bay, was created in 1994 by the merger of the municipalities of South Melbourne, Port Melbourne, and St. Kilda. Pop. (2006) Port Phillip local government area, 85,096; (2011) Port Phillip local government area, 91,372.