Coramba was a twin-screw steamer of 531 tons built in Ayrshire, Scotland, and launched on 15 August 1911 for the Belfast and Koroit Steam Navigation Company, which ran her between Melbourne and the Western District ports of Warrnambool, Port Fairy and Portland with wool, dairy produce and general cargo. On 29 November 1934 she left Warrnambool for Melbourne loaded with wool and condensed milk. Overnight the weather worsened into a furious storm; she never arrived, and over the following days deckhouse wreckage and bodies washed ashore on the southern coast of Phillip Island.

All seventeen aboard were lost, one of Victoria's worst shipwreck tragedies of the twentieth century, and the wreck's location remained a mystery. A diver, Johnno Johnstone, reported finding her in shallower water about 1.5 miles west of Seal Rocks decades later, but attempts to relocate that site failed. Southern Ocean Exploration searched for seven years and on 29 May 2011 found the Coramba about 10 nautical miles south of Seal Rocks in 66 m.

She lies north–south with the bow to the south, on her port side and almost upside down, so the dive is over the exposed starboard side and keel of an intact small steamer with her bow and stern and twin screws recognisable. Deep-water sponges and sea whips have colonised the hull and ling, boarfish and big crayfish live around it; visibility of 20–30 m is typical on the rare suitable days. The Coramba is a protected historic shipwreck and a grave, and it is an expedition dive: trimix or rebreather, an hour or more of decompression in open Bass Strait, and a long run from Newhaven or Western Port.

It is dived once or twice a year by experienced technical teams and suits only them; for everyone else the story is told at the Phillip Island museums and the memorial at Warrnambool.

Expedition only. Depart Newhaven ramp on Phillip Island (parking, toilets, fuel; Melbourne–Newhaven about 1 h 45 min via the Bass Highway) or Flinders/Hastings in Western Port and run south around Seal Rocks into open Bass Strait – about 25–30 km and an hour or more each way in a fast technical boat. Trips are private expeditions by Melbourne rebreather teams; there is nothing on the surface and the position is an approximate published mark, so a sounder search is part of the day.

Note that the Scuba Doctor's stated position (about 18 km south of Seal Rocks) and its GPS mark do not agree precisely – confirm before committing fuel.

Open Bass Strait south of Phillip Island, exposed to the full westerly and south-westerly swell and to the currents that run between the island and the Strait proper – the same waters in which the ship foundered in a 'furious storm'. A window needs swell under about 1 m and light winds for the day, plus slack or weak current for the shot-line work; such days come a few times a year, mostly in autumn. The hour-plus decompression is done on the shot or drifting under the boat.

Visibility at 66 m in clean offshore water is often 20–30 m.

Expedition trimix/CCR dive: descend the shot to the hull, which lies north–south on its port side and almost upside down with the bow to the south, survey the exposed starboard side and keel, the bow and the stern in 20 minutes without entering, and ascend the shot with 60–80 minutes of staged decompression.

Trimix (e.g. 15/55 or 12/60) or CCR with EAN50 and oxygen deco; 20 min bottom time gives 60–80 min of decompression. Historic shipwreck – no artefact recovery.

No operator. Located by Southern Ocean Exploration on 29 May 2011 after seven years of searching and dived since by a small number of Melbourne technical/rebreather teams, typically once or twice a year in autumn.