The 3 masted 725 ton barque hit a submerged rock on Five Fathom Bank during the night of the 28th December 1898 and sank almost immediately. The Sepia wreck remains one of the very few colonial era vessels in the metro area that still has cargo amongst the wreckage. The wreck lays in 15 metres of water 2 miles south west of Carnac Island. Usually visibility is low given its proximity to Cockburn Sound and the site is also exposed to swell. For the best dive experience, a good few days of low swell and offshore winds can vastly improve the conditions on the site.

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Due to the speed of the Sepia sinking, much of the cargo was deemed un-salvageable. On board it was carrying a large amount of alcoholic bottles mixed amongst a general cargo bound for the growing Swan River Colony. The site location has always been known and since the sinking much of the cargo and artefacts have been removed by the public in the days before the introduction of the Historic Shipwrecks Act. However, still to this day near the stern of the wreck, in the collapsed remains of the cargo hold and still visible, are hundreds of bottles still neatly stacked and nearby barrels lay stored neatly on their side, as they were the day the vessel sunk over a century ago. The easily accessible wreck remains protected from interference and removal of artefacts, protected under the Historic Shipwrecks Act.