North West Island is the largest coral cay on the Great Barrier Reef, covering about 91 hectares, and one of the most important green turtle nesting sites in the southern reef, with nesting from about October to December. It is a national park with Pisonia forest and a campground, and its reef offers self-sufficient divers a genuinely remote experience within reach of Gladstone. Marine life writers describe staghorn and soft coral gardens, giant clams, sea anemones and blue linckia starfish on the reef, with deep gutters on the southern drop-offs.

Turtles are common in and around the lagoon, especially in nesting season, and reef sharks and rays patrol the edges. Wedge-tailed shearwaters nest on the island in huge numbers. Diving here is not organised: there is no resort or dive centre, and access is by private boat, camping group or the occasional liveaboard passing through the Capricorn Group.

Shore diving from the campground is possible but involves a long walk across the drying reef flat in full gear, so most divers use a tender to reach the reef edge. The island suits experienced, self-reliant divers who can manage their own gas, safety and logistics, and campers who want to snorkel the reef flat at high tide. Anyone camping should be aware of seasonal restrictions to protect nesting turtles and seabirds, and of the national park rules on lights and access to the beach at night.

Combined with Tryon, Masthead and Wilson islands, North West Island forms part of a chain of cays that can be explored over several days by boat.

The Capricorn Group lies 60-100 km north-east of Gladstone. Private boats launch from Gladstone Marina (Bryan Jordan Drive; ramps, fuel and trailer parking) and cross the shipping approaches and open water, typically 2-4 hours depending on vessel and destination; the Capricorn Bunker liveaboards that occasionally visit depart Gladstone or Yeppoon (Rosslyn Bay) and anchor overnight in the lee of the cays. Camping on the national park cays requires a QPWS permit and a camper transfer or private vessel.

North West Island is roughly 75 km from Gladstone. Campers arrive by permit with camper transfers or private boats and camp at the island's national park campground (up to about 150 people). Shore diving involves a long walk across the drying reef flat in full gear to reach the edge, so boat dives from a tender are far more practical.

The Capricorn cays are exposed to the south-east trades (often 15-25 knots April-September), which make the Gladstone crossing rough and restrict diving to the lee (north-western) sides. The calmest windows are typically September-December and March-April. Northerlies in spring and summer reverse the sheltered sides.

Tidal currents run strongly around reef edges and channels on springs. Cyclone season November-April. The southern drop-offs face the trade winds and are dived in calm spells; the northern and western sides are more sheltered.

The reef flat dries at low tide, so shore dives must be timed for high water.

From a tender, descend on the southern drop-off and explore the deep gutters at 12-20 m, then rise into the staghorn and soft coral gardens on the reef slope for the second half. Shore divers should only attempt the reef-flat walk at high tide and plan the return before the tide falls.

No daily operator. Occasional liveaboard itineraries (for example the 8-diver MV Adori run by Professional Dive Services, 4 days/3 nights from Yeppoon) and fishing/snorkel charters such as Eastern Voyager visit the Capricorn cays; otherwise private boats and camping groups only. Liveaboards such as MV Adori have included North West Island on Capricorn Bunker itineraries.