Kangaroo Head, on the Dudley Peninsula between Penneshaw and American River, is singled out by the Marine Life Network as one of the best locations for leafy seadragons – a moderate-depth, easier dive on weedy reef to about 9 m (12 m maximum). For many visiting divers, the leafy seadragon is the reason to come to South Australia, and Kangaroo Island's clean, weedy reefs are prime habitat.

The reef is a mix of low rock, kelp and dense brown algae, with sand patches. Leafy seadragons, with their elaborate leaf-like appendages, drift among the weed and are easy to overlook; weedy seadragons also occur. The Marine Life Network lists boarfish, perch, morwong and invertebrates, and the reef supports wrasse, leatherjackets and the typical Gulf fish community. The moderate depth allows long, slow searches, which is exactly what seadragon hunting requires.

Seadragons are protected in South Australia, and photographers should avoid flash-heavy harassment, never touch or chase them, and keep fins well clear of the weed. The site is sheltered from the south-westerly swell, although easterly winds and Backstairs Passage currents need watching. Land access is limited by private property, so boats from Penneshaw or American River are the usual approach, and a local guide greatly improves your chances of finding dragons. It suits Open Water divers and photographers. Autumn and winter often bring the clearest water and are a good time for photography. Carry a light even in daylight to bring out the colours of the dragons and the invertebrates beneath the weed canopy, and dive in small groups to avoid crowding the animals.

Take the SeaLink ferry from Cape Jervis to Penneshaw (45 min). Kangaroo Head is on the north-west of the Dudley Peninsula, a short drive west of Penneshaw; the coast below the head is largely private farmland with steep access, so most divers go by boat from Penneshaw or American River and anchor in the lee depending on wind. Ask local operators about current access.

The Dudley Peninsula sites lie on Backstairs Passage and Eastern Cove, sheltered from the prevailing south-westerly swell but swept by strong tidal streams through the passage. Dive around slack water, particularly near headlands and islands; wind against tide creates steep chop. Easterly and north-easterly winds make Penneshaw and Hog Bay choppy, while south-easterlies affect Antechamber Bay and Cape Willoughby.

Summer and autumn bring the calmest days; winter westerlies are usually fine on this side of the island.

Anchor on sand beside the reef at about 9 m, then search slowly through the weed at 6-10 m for leafy seadragons, boarfish and perch; keep a light touch and good buoyancy near the dragons.

Leafy and weedy seadragons are protected species in SA – no handling or harassment.

Kangaroo Island Dive & Adventures (Kingscote) – guided dives and advice (confirm current trading) – has run guided leafy seadragon dives on KI; otherwise private boats.