Portarlington is a historic coastal township located on the Bellarine Peninsula, 28 km from the city of Geelong, in the state of Victoria, Australia. The gently rising hills behind the town feature vineyards and olive groves, overlooking Port Phillip Bay. Portarlington is a popular family holiday destination and a centre of fishing and aquaculture (mussels). At one time the town claimed the largest caravan park in the Southern Hemisphere, although the size has reduced considerably in recent decades. In the 2011 census, Portarlington (including Bellarine and the rural section of St Leonards) had a population of 3,580 people.