Outer Harbor, at the mouth of the Port River, is Adelaide's deep-water port, and the Marine Life Network lists its breakwater and wharf as a local dive site in about 10 m. Its main value is shelter: when westerly or south-westerly winds make the open metro coast undiveable, the breakwater provides protected water. The rock wall and wharf structures are colonised by soft corals and sponges, which is typical of port infrastructure where water movement brings plenty of food for filter feeders.

Around the rocks divers can expect fish such as old wives, magpie perch, leatherjackets and bream, and invertebrates in the crevices. The site lies close to the Adelaide Dolphin Sanctuary, which protects the Port River and Barker Inlet, and dolphins are common in the area. The drawbacks are significant.

Visibility is variable to poor, the shipping channel is close and must be avoided, and parts of the port are restricted commercial areas. Currents run at the river mouth. The Marine Life Network advises staying away from the shipping channel, and divers should check the current rules for public access to the breakwater before visiting.

Outer Harbor is best seen as a local fallback for experienced divers when everything else is blown out, rather than a destination. For divers launching at North Haven, the Norma wreck offshore is the better outing on calm days. If you do dive the breakwater, go with a buddy who knows the area, fly a dive flag, and time the dive for slack water with no ships expected; the port's vessel movement schedule can help.

Outer Harbor is about 30 minutes north-west of the Adelaide CBD via Grand Junction Road and Victoria Road, or by train to Outer Harbor station. Parts of the port are restricted commercial areas, so confirm current public access to the breakwater before going and stay out of fenced or signed port zones. Boats can launch at the North Haven ramp nearby.

Entry from the breakwater is over large rocks – choose a spot with a safe exit.

The breakwater shelters the site from westerly and south-westerly seas, which is why it is used when the open coast is blown out. Visibility, however, is usually poor to variable because of Port River water and ship movements, and is worst after rain. Tidal currents run at the river mouth, so dive near slack water.

Avoid times when large ships are manoeuvring.

Enter at a safe point on the sheltered side of the breakwater, follow the rock wall at 5-10 m with it on one shoulder, look for soft corals and sponges, and turn at half gas. Stay well away from the shipping channel.

No regular operator; listed by the Marine Life Network as a local bad-weather site.