A man walks through a tunnel of Google homepage logos at the Google campus near Venice Beach, in Los Angeles, California. Credit: Reuters/Lucy Nicholson
Now, they are trying to understand why the phantom island was included on nautical charts of the region.
Scientist Maria Seton, who joined the 25-day long voyage in a fruitless attempt to find the strip of land, said: "It's on Google Earth and other maps so we went to check and there was no island.
"We're really puzzled. It's quite bizarre.
"How did it find its way onto the maps? We just don't know, but we plan to follow up and find out," she said.
Australia's Hydrographic Service, which produces the country's nautical charts, says its appearance on maps and Google Earth could be the result of a human error which has been repeated down the years.
A spokesman for Google said: "The world is a constantly changing place and keeping on top of these changes is a never-ending endeavour."
The supposedly sizeable strip of land, which would have been within French territorial waters, does not appear on French government maps.
One possible explanation is that the island was a deliberate mistake by map makers in order to identify if their data had been stolen.