The Garden Island Ships' Graveyard, in the North Arm of the Port River, is one of the largest and most diverse ships' graveyards in the world. Around 25-26 vessels – sailing ships, steamships and iron barges launched between 1857 and 1920 – were abandoned here between 1909 and 1945 as the port modernised. Among them is the Santiago of 1856, described as the oldest intact iron-hulled sailing vessel, along with the wooden schooner Dorothy H Sterling (1920), the Glaucus, Sunbeam, Garthneill and the submerged Seminole.

Today the hulks lie among grey mangroves around Garden Island, inside the Adelaide Dolphin Sanctuary established in 2005, and the South Australian Government promotes the site as a paddling trail. A 5 km loop from the Garden Island boat ramp takes two to three hours and passes the main wrecks; the lower the tide, the more there is to see, with ribs, frames and iron hulls rising from the mud and shallow water. Resident Port River dolphins are frequently seen.

The graveyard was included in this region's list for completeness, but none of the dive sources consulted describe it as a dive site. The Port River is turbid and silty, visibility is typically close to nil, commercial and recreational boats use the channels, and the hulks are protected historic heritage. It is best experienced by kayak or small boat, and snorkelling or diving is not recommended.

For divers interested in maritime history, the graveyard complements the Norma and John Robb offshore, and the Yankalilla Bay and other ships' graveyards around the state. Visit on a calm day at low tide, and take a kayak tour if you are new to the area.

From Port Adelaide drive north on Port River Expressway/Garden Island Road to the Garden Island boat ramp (about 25 minutes from the CBD). The North Arm Ships' Graveyard paddling trail starts at the ramp and loops about 5 km past the hulks, taking 2-3 hours. The ramp is busy with powered craft, so paddle close to the edge of channels.

Go at low tide, when more of the wrecks are exposed. Guided kayak tours operate from Port Adelaide.

A sheltered mangrove estuary, so wind waves are small, but strong winds make paddling hard work. Low tide exposes more of the hulks and a sandbar to the west of the Dorothy H Sterling. Tidal streams run in the channels.

Water clarity in the Port River is typically very poor, with fine silt and high turbidity, especially after rain.

Paddle the marked 5 km trail from Garden Island boat ramp at low tide, viewing the hulks from the surface. Diving is not recommended.

No dive operator runs trips; kayak tours (e.g. Seven Senses Adventures and other Port Adelaide kayak operators) take paddlers around the hulks and dolphin sanctuary.