Meet the site
The Glenelg Blocks are a line of hollow concrete blocks running parallel to the beach about 500 m off Glenelg, the remains of an old ship mooring system associated with the early Glenelg jetty era. They are spaced over about 200 m in only 5-6 m of water, and at low tide their tops can be seen breaking the surface. What makes the Blocks worth a dive is the life that has made them home. Wobbegong sharks are almost always found resting in and around the blocks, according to the Sea Wolves, and the concrete is covered with algae, sponges and small invertebrates. The sand between is classic muck-diving ground: the Federation describes it as an interesting second dive and an excellent muck dive. At night the site changes character, with dumpling squid, octopus, southern calamari, sea stars and urchins emerging. The southern pillars have small swim-throughs. Being so shallow and so close to Glenelg, the Blocks are a common choice for second dives after the Dredge, for night dives, for training and for divers wanting a long, relaxed hour looking for small things. The flip side is visibility: the site is readily stirred up after strong winds and affected by runoff from the Patawalonga. Pick a calm morning after easterlies. Boats are the practical way to visit, but experienced swimmers can reach the Blocks from the beach on a calm day. Either way, fly a flag or use a surface marker buoy, because this is a busy stretch of water with jet skis, fishing boats and boats heading in and out of Holdfast Shores marina.
What you might see
Wobbegong sharks, dumpling squid (night), octopus, southern calamari, sea stars, urchins, cuttlefish, blennies, leatherjackets, nudibranchs
Location
Row of concrete mooring blocks running parallel to the shore about 500 m off Glenelg, between the jetty and the Patawalonga/Holdfast Shores entrance; the tops show at low tide.
Facilities nearby
Glenelg foreshore: paid parking, toilets and showers near the jetty and Holdfast Shores, many cafes; air fills at Adelaide Scuba (Glenelg North) and The Dive Shack.
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
seawolves.org.ausdfsa.netthediveshack.com.aumarinelife.org.auen.wikivoyage.orgdivedb.netRecord updated 26 Sept 2026. Source claims are being reviewed.