Halfway Island is a small island lying between Great Keppel and Humpy Island, and its south-western side holds a fine staghorn coral garden at about 7 m. It is a gentle, shallow dive in a location sheltered by the surrounding islands, and it is often chosen when the wind rules out more exposed sites. The staghorn thickets form a dense field of branching coral that shelters clouds of small fish, including damsels and chromis, while parrotfish and angelfish graze and patrol around the edges.

Feather stars cling to the coral tips, tube worms and nudibranchs are scattered through the reef, and sea snakes and turtles are regular visitors. The dive is simple: descend to the garden and meander across it, keeping good buoyancy to avoid breaking the fragile branches. Depth rarely exceeds 10 m, so bottom times are long and there is plenty of light for photography.

Halfway Island suits new divers, snorkellers in good visibility, and anyone who wants to see a healthy branching-coral community typical of the sheltered Keppel reefs. The nearby Half Tide Rock, off Great Keppel's northern coast, is often confused with it in older listings but is a separate site. Because inshore staghorn fields respond quickly to both damage and recovery, the condition of the garden can change from year to year after floods or bleaching; ask the operator about its current state.

Halfway Island is often paired with Humpy Island, a few minutes away, whose southern side offers several additional sheltered sites for a second dive on the same trip.

Drive 40 km (about 40 minutes) from Rockhampton to Yeppoon, then 7 km south along the Scenic Highway to Keppel Bay Marina at Rosslyn Bay Harbour, where there is free and paid parking. Freedom Fast Cats and Keppel Konnections ferries run to Great Keppel Island (Fisherman's Beach) in about 30 minutes; Keppel Dive & Water Sports picks up certified divers from the island. Halfway Island lies just south of Great Keppel, between it and Humpy Island, about 10-15 minutes by dive boat from Fisherman's Beach or 30 minutes by private boat from Rosslyn Bay.

Boats anchor on sand off the south-west side.

Keppel Bay is exposed to the prevailing south-east trades (strongest April-September) and to summer northerlies. The south-west side of Halfway Island is sheltered from south-easterlies and from northerlies by Great Keppel and Humpy Island, making it a useful fallback site. Tidal flow runs between the islands on springs.

Visibility 5-12 m, lower after rain.

Descend onto the staghorn garden at around 7 m and slowly explore the thickets, keeping well off the fragile branches. Follow the garden along the island's edge, turn at half air and return shallower for the safety stop.

Keppel Dive & Water Sports (PADI 5 Star, based on the Spit at Great Keppel Island next to Great Keppel Island Hideaway) runs guided boat dives to the Keppel sites most days, weather permitting, plus courses and Discover Scuba; site choice is made on the day according to wind. Private boats from Rosslyn Bay also dive here. Often combined with a dive at nearby Humpy Island.