Shiprock is probably Sydney's most famous estuary dive, and in Ship Rock Aquatic Reserve all marine life is protected. It sits at the junction of Burraneer Bay and Port Hacking, off the end of Shiprock Road, Dolans Bay, and takes its name from a rock outcrop said to resemble a ship's hull. Because of the strong tidal flow the dive is done only at high tide, and the timing ritual – enter exactly at the predicted peak, about 20 minutes after Fort Denison – is part of the experience.

From the entry the bottom starts at 2–3 m, drops to about 6 m and then falls suddenly to almost 15 m. Along the wall are overhangs and a small bubble cave at 15 m, and offshore a series of bommies, about 10 m apart, rise from sand that reaches 18 m at the base of the rocks. Further along the wall, submerged tree stumps and wharf pilings add interest.

The fish life is outstanding for an estuary: every type of leatherjacket, bream, luderick, trevally, John Dory, flathead and schools of more than 100 sand whiting. The invertebrates are as good – decorator crabs, spider crabs, hermit crabs, nudibranchs in large numbers – along with moray and conger eels. Pineapplefish turn up irregularly; McFadyen saw 30 on one dive in 2002 but none between 2016 and 2021.

A green turtle visited in 2007. Visibility has improved since the 1990s and now averages around 10 m. The biggest hazard is power boats: on weekends dozens pass directly over the site, so divers must never surface away from the wall, even if separated from a buddy.

The superb stairs make access easy. It suits Open Water divers, macro photographers and night divers (before the gate closes), and it remains a Sydney rite of passage.

Drive to Caringbah, then Port Hacking Road south and turn into Shiprock Road at Dolans Bay; park as close to the end of the cul-de-sac as possible (spaces are limited and taken early on weekends – arrive at least 30 minutes before high tide). Walk down the excellent stairs (rebuilt in April 2012) to the waterfront. Entries: the stone steps behind the rock, the high steps at the old boat ramp (awkward at lower tides), the concrete platform (needs at least a 1.7 m tide) or the pool entry.

A gate closes the reserve from 9.30 pm to sunrise and alcohol is prohibited in the reserve and street.

Shiprock is inside Port Hacking and unaffected by ocean swell, so it can be dived in almost any weather – the tide is everything. Strong tidal currents flow past the rock, so dive only at high slack: enter exactly at the predicted peak, which is about 20 minutes after Fort Denison high tide, and plan 50–60 minutes (70 is easily achievable). After heavy rain the turn can be delayed by up to 40 minutes, and very large easterly seas also delay it.

Visibility averaged 5–7 m in the 1990s but has been around 10 m since 2000, occasionally over 20 m; it is poor after heavy rain.

Enter at high slack and head east from the entry across the 2–3 m shallows to the drop at 6 m and the wall falling to almost 15 m. Visit the offshore bommies (about 10 m apart) and the small bubble cave at 15 m, then follow the wall south past overhangs, and west past tree stumps and wharves for about 30 minutes before returning along the wall to the pool exit. If lost, head north-west to find the wall and shallows.

Pro Dive Cronulla runs regular guided high-tide dives and courses; Abyss, Sydney Dive Academy, Frog Dive and many clubs schedule Shiprock on every suitable high tide.