Meet the site
Seal Cove is the signature seal encounter at Althorpe Island. The Marine Life Society describes it as a fairly narrow cove with a huge seal population – more than 150 animals – that are playful and used to divers, sometimes letting divers pat them, and calls it a great dive to finish off a cylinder. It also mentions two of the biggest and friendliest western blue groper in the area. Visitor information lists gropers, boarfish, rays and crayfish alongside the colony. The seals here are principally long-nosed (New Zealand) fur seals, with Australian sea lions also present around the Althorpes. In the water they twist and dive around divers, blowing bubbles and mouthing fins, and the shallow, sheltered cove means divers can simply settle on the bottom at 8-12 m and watch. The cove walls carry kelp and sponges, and the bottom holds boarfish, rays and crayfish. Modern practice is to let the animals approach rather than touching them, and to avoid disturbing haul-outs. White sharks are drawn to seal colonies in South Australia, so divers should stay aware and keep dives compact. Because it requires the crossing to Althorpe, Seal Cove is an occasional expedition site. When conditions allow, it is one of the most memorable marine mammal dives in the state. Snorkellers can also enjoy the seals from the surface on a calm day, although the animals are most playful when divers settle quietly on the bottom. Summer and early autumn, when pups born on the island are learning to swim, are especially lively. Keep dives relaxed, avoid chasing animals, and leave the cove if seals show signs of stress, such as bulls barking and charging.
What you might see
New Zealand (long-nosed) fur seals (150+), Australian sea lions, western blue groper, boarfish, rays, southern rock lobster, kelp, sponges
Location
Narrow cove on Althorpe Island with a large, diver-habituated seal population and resident big blue groper, in 8-15 m.
Facilities nearby
None.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
marinelife.org.auvisityorkepeninsula.com.auRecord updated 26 Sept 2026. Source claims are being reviewed.