The Geltwood is one of South Australia's most tragic shipwrecks and, according to the Marine Life Network, one of its most spectacular wreck dives – on the rare days it can be dived. An iron, three-masted barque of 65.7 m and 1,056 net tons, she was launched on 18 January 1876 by R. Williamson & Sons at Harrington and was completing her maiden voyage from Liverpool to Melbourne when, in a storm on 14 June 1876, she struck a reef, capsized and broke up off the Canunda coast. All 31 passengers and crew were lost. Authorities only learned of the wreck on 5 July, after nearly three weeks in which washed-up cargo was looted from the beaches.

The wreck lies about 1.6 km offshore near the northern end of Lake Bonney, 16 km south-east of Southend. Divers who have reached it describe a recognisable hull with masts, yards, anchors and concreted cargo – unusual for an iron wreck on such an exposed coast. The Marine Life Network is candid that it is undiveable most days because of continual swell, and there is no charter.

Anchors and memorabilia are displayed at the Geltwood anchor memorial on Cape Buffon Drive at Southend, the Millicent Living History Museum and the Beachport museum, and the wreck's 150th anniversary in 2026 prompted a documentary and commemorations. The site is a protected historic shipwreck: look, photograph and leave everything in place. It suits experienced, self-sufficient boat divers who can wait for a genuine flat calm on the Southern Ocean.

There is no charter. Launch a suitable private boat from Southend (about 70 km north-west of Mount Gambier via Millicent) and run south-east along the Canunda coast about 16 km to the wreck, 1.6 km off the beach near the northern end of Lake Bonney, using the published GPS position. It is a long run along an exposed surf coast with no shelter, so only attempt it in a flat calm with a reliable weather window and a second vessel if possible.

The Limestone Coast faces the full Southern Ocean, and prevailing south-westerly swells of 2-4 m are the norm, especially May-October. Shore and boat dives need a genuine calm spell: swell under about 1 m, light winds, ideally northerly or north-easterly offshore breezes, and a few settled days for visibility to recover. Summer south-easterly sea breezes build most afternoons, so dive early.

Heavy winter rain brings tannin-stained run-off from drains and creeks that reduces visibility near shore. Autumn (March-May) usually has the most calm days and the best visibility. The Marine Life Network notes the Geltwood is undiveable most days because of continual swell.

Anchor off the wreck site in sand, descend, and survey the recognisable hull sections, masts, yards, anchors and concreted cargo; do not disturb anything. Ascend on the anchor line.

Protected historic shipwreck (SA/Commonwealth heritage legislation) – no souveniring; check for any protected zone permit requirement.

No regular operator – private boat only; rarely dived because of the swell.