Meet the site
Middle Island sits in the mouth of the Merri River on the western side of Stingray Bay, a low rock islet famous above water for the little penguin colony that was saved from foxes by maremma guardian dogs – the story behind the film Oddball. Below water it is the richest part of the Merri Marine Sanctuary. Between Middle Island and its neighbour Merri Island runs a deep canyon reaching about 15 m, and Parks Victoria's description of it – kelps swaying with the waves, colourful sponges beneath the overhangs – understates a slot packed with life. The Scuba Doctor describes boulders, channels, overhangs and swim-throughs, and lists Port Jackson sharks, gulf wobbegongs, stingrays, giant Australian cuttlefish, parrotfish (rainbow cale), zebrafish, southern rock lobster and abalone as the common residents; add the draughtboard sharks, eagle rays, seahorses and schooling sweep of Stingray Bay, and the fur seals and dolphins that come in from outside. From August to February little penguins and short-tailed shearwaters breed on the island and the penguins can be seen hunting in the sanctuary waters at dusk.
Two dives are possible. The sheltered option is to swim from Stingray Bay into the channel and dive the canyon, which is protected enough to be done on many low-swell days and is a straightforward Intermediate dive with a strong sense of place. In very calm conditions experienced divers continue around to the exposed Southern Ocean side of the island, where kelp forests and bigger fish face the open sea; this side, the Scuba Doctor warns, turns into dangerously rough water with big swells and strong currents when conditions deteriorate, and it should only be attempted after watching the sea for a while. Both dives start and finish at the Stingray Bay steps. The island itself is closed to the public and landing is prohibited; the sanctuary is no-take throughout. For most visiting divers the canyon is the single best dive in Warrnambool that can be done from shore.
What you might see
Port Jackson sharks, gulf wobbegongs, draughtboard sharks, stingrays and eagle rays, giant Australian cuttlefish, rainbow cale (parrotfish), zebrafish, southern rock lobster, black-lip abalone, sea sweep, little penguins and short-tailed shearwaters (Aug–Feb), Australian fur seals, kelp, sponges under overhangs
Location
Small island at the mouth of the Merri River with a 15 m deep canyon between it and Merri Island, inside the Merri Marine Sanctuary; home to the maremma-guarded little penguin colony.
Facilities nearby
Large car parks off Viaduct Road and at the breakwater; toilets and showers at the breakwater and Stingray Bay; Warrnambool Diving (179A Fairy Street) for air fills, gear and guided dives; Pavilion cafe at the breakwater; Flagstaff Hill Maritime Museum nearby.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
scubadoctor.com.auparks.vic.gov.auvisitvictoria.comRecord updated 26 Sept 2026. Source claims are being reviewed.
