Pinnacle Reef is a private mooring about 1 km offshore from Green Island used exclusively by Ocean Free, a small sailing vessel operated by Cairns Premier Reef and Island Tours that carries a maximum of 25 guests. The operator describes a stunning coral garden with corals, clams, fish, stingrays and green and hawksbill turtles, and pairs it with a visit to Green Island on the same day. Because only one small boat uses the mooring, the site is quiet and the coral shows little diver damage, which is a contrast with the busier beach sites on Green Island itself.

The reef consists of coral pinnacles and patches rising from a shallow sandy bottom, forming a coral garden that is ideal for snorkelling and for introductory and newly certified divers. Giant clams sit among the coral, blue-spotted stingrays rest on the sand, and turtles, both greens and the smaller, hook-beaked hawksbills, are regularly seen. The reef fish community includes parrotfish, wrasse, damselfish, butterflyfish and anemonefish.

Depths are modest, and published detail on the site is limited to the operator's description, so the depths given here are estimates. Like other reefs close to Cairns, visibility is lower than on the outer reef, typically 8-15 m, and it drops after heavy rain. The site suits people who prefer a small-group sailing day with a relaxed pace over a large pontoon or fast catamaran.

Exact coordinates of the mooring are not published. Stinger suits are advisable from November to May, as on all reefs near Cairns.

Boat access only. Cairns day boats leave from the Reef Fleet Terminal (1 Spence Street) and the neighbouring Marlin Marina on the city waterfront, with check-in between about 7:00 and 8:00 am; most operators run transfers from city and northern-beaches accommodation, and there is paid parking near the terminal. The run of about 28 km out through Trinity Inlet and across the lagoon to Pinnacle Reef takes around 90 minutes on a fast catamaran and noticeably longer on slower dive boats or into a south-easterly chop.

Pinnacle Reef is an exclusive mooring for Ocean Free, a sailing vessel carrying a maximum of 25 guests, which also visits Green Island on the same day. Enter from the stern steps.

The prevailing south-east trade winds (typically 15-25 knots from April to September) are what limit Cairns outer-reef diving: above about 25 knots trips may be cancelled, and exposed eastern moorings are used only in light winds. Summer northerlies are gentler but make north-facing moorings choppy. Box jellyfish and Irukandji are present from about November to May (stinger suits on every dive), and the cyclone season runs November to April, when a system in the Coral Sea can close the reef for days.

Visibility drops after heavy rain and strong winds; spring is usually calmest and clearest. Being closer to the coast, visibility is lower than on the outer reefs, especially after rain. Pinnacle Reef lies close to Green Island and is dived in most trade-wind conditions; visibility is typically 8-15 m and lower after rain.

Descend from the mooring onto the coral garden and explore the pinnacles at 5-10 m, watching for turtles and stingrays on the sand edges. Return to the boat through the shallow garden with a safety stop.

Ocean Free (Cairns Premier Reef & Island Tours) – exclusive private mooring, max 25 guests; snorkelling and introductory/certified diving; Big Cat Green Island and Great Adventures run dives from the island itself for those who prefer a beach entry; the mooring used on any day is chosen by the skipper according to wind, tide and other boats