The 336m-long hull floated out of the dry dock at Daewoo's Geoje shipyard on Sunday.
"Prefabricated blocks weighing around 60,000 tonnes in total have been lifted into the dry dock and assembled to create the full-size FPSO hull we see on the water today," Ichthys LNG project offshore director Claude Cahuzac said.
"While the hull is now at its full length from stern to bow and floating, it does not mean the FPSO is complete.
"We still have some work to do to complete the hull and even more for the entire FPSO, including the fabrication and integration of the topsides, living quarters and our next major milestone - the installation of the turret, which is currently under construction in Singapore."
The FPSO is designed to hold more than one million barrels of condensate and house a workforce of up to 200 people.
Construction of the FPSO and the project's central processing facility - which will become the world's largest semi-submersible platform - are expected to hit a shared milestone in the December quarter with their topsides to be lifted onto their hulls.
The Inpex-operated project is targeting 8.4 million tonnes per annum of LNG capacity from the two planned trains near Darwin, along with 1.6MMtpa of liquefied petroleum gas and about 100,000 barrels of condensate per day from the Ichthys field at its peak.
Ichthys' reservoirs are about 200km off Western Australia's coast in the Timor Sea and host an estimated 12 trillion cubic feet of gas and 500 million barrels of condensate.
