The Edinburgh Castle was a three-masted iron barque of 627 tons, built by J G Lawrie at Glasgow in 1863 and employed for most of her life in the Clyde–China–Singapore trade. In January 1888 she arrived off Warrnambool, 101 days out from Liverpool, with a cargo of some 5,000–6,000 barrels of Portland cement for the construction of the town's new breakwater. On 15 January, in calm weather, a mistake by the pilot put her aground on the sand in Lady Bay. The coastal steamer Julia Percy tried to tow her off and cargo was jettisoned to lighten her, but she settled into the sand and broke up in the rough weather that followed. Her loss was an embarrassment to the harbour scheme she had come to serve, and she was forgotten until divers Peter Ronald and Colin Goodall relocated her in November 1985, nearly a century later.

The wreck lies broadside to the beach in soft, mobile sand in 4–5 m, bow toward the Hopkins River mouth, covering an area of about 30 by 40 m. A windlass and an anchor mark the bow and a winch the stern; between them lie scattered hull remnants and, most distinctively, the cargo. The wooden barrels rotted away long ago, but the cement inside them had set, and the site is dotted with perfect cylindrical concrete casts of the barrels, hoops and stave marks still visible. Sand covers and uncovers the wreck from year to year, so the amount exposed varies. Marine life is sparse on a sand site in surge – a few wrasse and leatherjackets around the iron, rays on the sand – and the interest is entirely in the story and the barrels. It is one of only three of the twenty ships believed lost in Lady Bay to have been found (with the Free Trader and the La Bella), it is protected under the Heritage Act, and it is a pleasant, shallow second dive from a boat on a flat day, though the Scuba Doctor's warning that the area is extremely dangerous in any swell should be taken literally.

Launch at the Warrnambool (Lady Bay) boat ramp beside the breakwater at the end of Viaduct Road and run east across the bay for about 2 km, ten minutes, to the position off the eastern end of Lady Bay beach. Anchor on sand; the wreck is low and easily missed, so use a sounder or the published GPS. A shore dive is possible from the eastern end of Lady Bay beach (park at the Surfside holiday park or Granny's Grave) with a surface swim of several hundred metres, but only in nil swell.

Warrnambool Diving on Fairy Street supplies air.

The Scuba Doctor states there are no underwater hazards but that this region is extremely dangerous in any swell: the site is prone to heavy surf and the surge is usually strong. At 4–5 m in the eastern half of Lady Bay the wreck sits where the south-west swell shoals and breaks, so it is only sensibly dived when the swell is under about 0.5 m and the wind is light and northerly. Visibility is limited by the soft mobile sand that continually covers and uncovers the site, and by Hopkins River run-off after rain.

Best on a high tide in a settled autumn spell. The wreck may be largely buried after a run of big seas.

Anchor on sand close to the published position, descend and search in a widening circle until you find the windlass and anchor that mark the bow, which points south-east toward the Hopkins River. Follow the line of hull remnants and concrete barrels across the 30 by 40 m site to the stern winch, then work back to the anchor. Turn at half gas; there is no need for a safety stop at this depth.

Warrnambool Diving – occasional guided dives; local club divers with private boats. No scheduled charter.