West Island is a 10-hectare island of rounded and jointed granite about 1.5 km south-west of the Bluff, the outermost island of Encounter Bay. According to the Marine Life Network, the north side is boulder-strewn, the rest of the island is ringed by 40 m cliffs, and a granite quarry operated on the northern side from 1883 until the 1960s. The island is a conservation park with a New Zealand fur seal colony, a little penguin colony, crested terns and silver gulls, and it has long been used for research, with a research jetty on the north side.

The surrounding waters became an aquatic reserve in 1983 and are now part of Encounter Marine Park. Divers must observe strict restrictions: there is no diving between Restless Point and Penguin Rock (the whole north-west side), and entry to Abalone Cove is banned because of ongoing research. The south and east sides are where the diving is.

Huge granite boulders drop to 20-25 m, carrying gorgonians, sponges, starfish and ascidians, and the Marine Life Network notes unusual fish life for the region, reflecting the colder, more oceanic water. Fur seals from the colony are likely to investigate divers. West Island is rarely visited by local divers, which adds to its appeal for experienced boat divers seeking something different.

It is exposed, deeper and colder than the inner bay, so it suits Advanced divers with their own boat on a calm northerly day. Treat the island and its wildlife with care, and check current zoning before diving.

Boat access only. Launch at the Bluff boat ramp, Encounter Bay, and run about 1.5 km south-west (roughly 10 minutes) to the island. Dive only on the south and east sides: diving is not allowed on the whole north-west side between Restless Point and Penguin Rock, and entry to Abalone Cove is banned because of ongoing research.

There is a research jetty on the north side; do not land without permission. Anchor in sand clear of the boulders.

Encounter Bay faces south into the Southern Ocean swell that wraps around Kangaroo Island and Cape Jervis, so Victor Harbor sites are the reverse of the gulf coast: they need northerly (offshore) winds. The best days follow several days of northerlies with low southerly swell, when visibility improves and the swell is blown back; any southerly or south-westerly swell over about 1 m, or strong southerly winds, makes most sites undiveable and stirs up particles. Summer and autumn bring the most northerly days, but good windows also occur in winter ahead of cold fronts.

Tidal currents strengthen around the headlands and islands during large tidal movements. Southern right whales visit Encounter Bay from about June to October – keep legal approach distances. Water is a little cooler than in the gulf.

West Island is more exposed than the inner bay and its waters are generally colder than the gulf; it needs a calm day with low swell.

Anchor off the south or east side, descend to the base of the boulders at 20-25 m and work up the boulder slope, exploring gaps and overhangs, finishing shallow. Stay well clear of the closed north-west side and Abalone Cove.

No regular operator; rarely visited by local divers (private boats only).