The Pinnacle is one of the traditional Terrigal boat dives, a self-contained lump of reef sitting in open sand about 1.9 km off Bateau Bay. The Terrigal Underwater Group describes it as a lump of reef that can be easily circumnavigated and lists it as one of the most popular dives in the area, and before the ex-HMAS Adelaide was scuttled in 2011 it was a staple of the commercial operators' reef rotation. Michael McFadyen notes wryly that the name is about as unoriginal as NSW dive-site names get, but the site itself is a good one.

The appeal is navigational simplicity combined with good structure. Because the reef is compact and surrounded by sand, divers can drop down the line, find the sand edge at around 22-24 m and simply follow it around, knowing that the anchor will reappear at the end of the lap. Along the base the rock is undercut into ledges and small overhangs, and boulders at the sand line shelter wobbegongs, eastern blue gropers and schools of one-spot pullers and ladder-finned pomfrets.

The top of the pinnacle is shallower and flatter, with sponges, ascidians and small gorgonian fans in the more current-swept areas and kelp patches in the lee. Muddy Puddle Diver, a local Terrigal blog, calls it a beautiful site with great reef structure and diverse fish and macro life, and nudibranch hunters do well in the cracks on the sides of the lump. Yellowtail and silver sweep hang in the water column over the top, and in warmer months kingfish sometimes sweep through.

Because it is small, the dive rewards a slow pace: a single careful lap at the sand line followed by time on the top is the usual plan. It suits Advanced divers or Open Water divers with a guide who are comfortable at 20 m-plus, and it is a sensible reef alternative when the Adelaide is crowded.

All boat dives in this area launch from the Terrigal Haven boat ramp at the southern end of Terrigal Beach, tucked behind The Skillion headland. From the Central Coast Highway follow Terrigal Drive into Terrigal, then Kurrawyba Avenue and Terrigal Esplanade to The Haven, where there is a paid car park beside the ramp; Pro Dive Central Coast's shop is a short walk away and gear is loaded on the ramp or the adjacent beach. Private boats need a ramp with good parking early on weekends as the car park fills by mid-morning in summer.

From The Haven the boat runs north past Wamberal, Forresters Beach and Crackneck Point to Bateau Bay - roughly 12-15 minutes in reasonable conditions. The site sits about 1.9 km off the centre of Bateau Bay Beach; McFadyen publishes the mark as 33°23'23.0"S 151°30'10.1"E.

Terrigal's offshore reefs are open to the Tasman Sea and are dived only when swell is below roughly 1.5 m; a north-east sea breeze building through the afternoon in summer and strong southerlies after a front are the usual reasons trips are cancelled, so morning departures are the norm. The Haven boat ramp is sheltered by The Skillion but the run out past the headland can be lumpy in a south-easterly. Visibility is best in late summer and autumn when the East Australian Current pushes warm blue water inshore, and worst after heavy rain when Terrigal Lagoon, Wamberal Lagoon and Avoca Lagoon open and stain the inshore water.

Winter water is cooler (around 15-17 °C) but often clear.

Descend the line to the top of the pinnacle, then drop to the sand line at about 22-24 m and circumnavigate the lump, keeping the reef on one shoulder. A full lap takes 20-25 minutes at a relaxed pace; finish by working up the shallower top and ledges before returning to the line for the ascent and a safety stop at 5 m.

Pro Dive Central Coast (Terrigal Haven) runs boat dives from The Haven most days, weather permitting; Central Coast Divers also runs Terrigal charters; the Terrigal Underwater Group dives the site from club and members' boats. It is usually offered as a second dive or when conditions or demand favour reef sites over the ex-HMAS Adelaide.