Shag Rock is Point Lookout's workhorse dive: close to shore, the most protected of the boat sites and diveable when almost everything else is blown out. It is an exposed rocky islet – in fact two small islands, visible from Cylinder Beach – with reef in 6-20 m around it, averaging about 10 m. Its best-known feature is a swim-through cave that runs through the rock and links both sides, which Manta Lodge calls spectacular.

There are also gullies and further swim-throughs, including a shallow gully on the south-eastern side at about 4 m. Despite being inshore and heavily dived, it is full of life. Manta Lodge lists wobbegong and bamboo (epaulette-type cat) sharks, eagle and bull rays, turtles, octopus, eels, nudibranchs, stonefish, sea urchins, corals and tropical fish, with occasional leopard sharks, manta rays and, in season, grey nurse sharks.

Gold Coast Dive Adventures adds electric rays, frogfish, porcupinefish, anemones and pelagic fish, and Australia Dive mentions loggerhead and hawksbill turtles, shrimps and squid. Adreno notes it is good for night diving. Because it is shallow and sheltered, Shag Rock is used for open water training and for divers who want an easy, long dive, but it also rewards experienced divers and photographers with its macro life.

Visibility is its main weakness: inshore water can be green and limited after rain or rough weather, though it clears in winter and after calm spells. It is a good first dive of a Straddie weekend and an excellent night dive. It is also close enough for a quick afternoon dive.

Drive to Cleveland (about 40 minutes from Brisbane) and take the SeaLink vehicle ferry or a passenger water taxi across to Dunwich on North Stradbroke Island, then drive about 20 km (25 minutes) east to Point Lookout. Manta Lodge & Scuba Centre at Point Lookout runs the dives, beach-launching its boats and reaching the Point Lookout sites in roughly 5-15 minutes. Brisbane operators (Brisbane Scuba from Manly, Gold Coast Dive Adventures from Runaway Bay) also run occasional day trips.

Shag Rock is visible from Cylinder Beach and is about 6-8 minutes from the beach launch; boats moor between the two islets on the north-western side.

The most protected of the Point Lookout boat sites and the fallback when Flat Rock, Manta Bommie and Boat Rock are rough. Still exposed to swell: easterly or north-easterly swell over about 2 m and strong northerlies make it surgy. Current is minimal.

Visibility is variable inshore (5-25 m, often around 7-10 m), improving in winter and after calm weather, and dropping after rain.

Moor between the islets on the north-western side, descend to about 8-10 m and swim around the rock, passing through the swim-through cave that links both sides and exploring the south-eastern gully at about 4 m. Return to the mooring for the safety stop.

Manta Lodge & Scuba Centre – daily, and the usual choice for training, beginners and marginal conditions; Gold Coast Dive Adventures – Straddie trips.