The western Victorian coast experiences southern ocean storms and high wave action. The eastern coast is more sheltered from wind and storms by Tasmania and the shallow waters and islands of Bass Strait. The eastern Victorian coastline is also influenced by warmer water that flows from northern Australia via the East Australian Current.
Many of the features of the Victorian coastline and sea floor reflect the cumulative effects of processes that began with the breaking up of Gondwanaland 50 million years ago, especially changes in sea level over the last 100,000 years. The 30 or more bays, inlets and estuaries along the coast were formed by the inundation of coastal river valleys after the end of the last Ice Age.
Victorian marine waters extend to three nautical miles offshore, with the depth varying from 30 metres to just over 100 metres.