what is the max distance (in Kms) to the shoreline from any point in australia?

Answer 1

This site shows different ways of determining the centre of Australia, including the furthest point from the ocean:
http://www.ga.gov.au/education/facts/dimensions/centre.htm#furthest

Unfortunately, it doesn't say how far this is! Using the measuring tools on Google Earth, it seems the furthest point from any shoreline is about 950km.

Answer 2

Although it is a long way from north to south or east to west, the indentations in the coastline like the Gulf of Carpentaria, Spencers Gulf and the Bight mean that nowhere in Australia is more than about 900km from the coast in a straight line.

Answer 3

Did want the longest distance from shore to shore?

From the Australian Bureau of Statistics.
http://www.abs.gov.au/AUSSTATS/abs@.nsf/Latestproducts/BE2857976E4D24EACA2570DE000314A3?opendocument

GEOGRAPHY OF AUSTRALIA

POSITION AND AREA

Australia comprises a land area of almost 7.7 million square kilometres (sq km) (table 1.1). The bulk of the Australian land mass lies between latitudes 10 degrees 41 minutes (10°41´) south (Cape York, Queensland) and 43°38´ south (South East Cape, Tasmania), and between longitudes 113°09´ east (Steep Point, Western Australia) and 153°38´ east (Cape Byron, New South Wales). The most southerly point on the mainland is South Point (Wilsons Promontory, Victoria) at 39°08´ south.

The latitudinal distance from Cape York to South Point is about 3,180 kilometres (km), and to South East Cape 3,680 km, (North to South)

while the longitudinal distance between Steep Point and Cape Byron is about 4,000 km. (West to East)

Answer 4

it's only half a click from my front door.