Cable Bommie – spelt 'Cable Bonnie' on the official tourism listing and called 'Cables' by Diveplanit – combines a healthy coral bommie with relics of Direction Island's history as a cable station. The depth range is 14–25 m. From 1901 Direction Island housed the Eastern Extension Telegraph Company's cable station, a relay on the submarine telegraph linking Australia with Africa and Asia, and it was this station that the German cruiser SMS Emden sent a landing party to destroy in November 1914, leading to the Battle of Cocos.

Lying on the reef at this site are lengths of cable and two large winches which, according to the official listing, are believed to have been used in the cable operations. The winches are heavily encrusted and now serve as reef structure, and the cables run across the bottom, gradually being overgrown. Around the man-made features, the reef has colourful fish and coral; Diveplanit notes the many hiding spots in the structures, and lionfish shelter in the winches and under ledges.

Grey reef sharks patrol the surrounding water. The site is a moderate-depth, relaxed dive suitable for Open Water divers, and the history adds interest for divers who have visited the cable station remains on Direction Island at lunchtime. The published GPS for Cable Bommie is identical to that of Winter Wall, suggesting the two are neighbouring parts of the same stretch of reef, possibly dived as a single outing.

Photographers can make interesting images of the encrusted winches with fish, and the mix of history and reef makes it a rewarding dive. The cables and winches are heritage objects: look but do not move or remove anything.

Fly to West Island on the twice-weekly Virgin Australia service from Perth (usually routed via Christmas Island; allow 7–10 days on the islands to absorb weather and flight delays). Cocos Dive collects divers from West Island accommodation in the morning (pickup around 8 am, departure about 9 am) and runs its boats from West Island into the lagoon. These sites lie along the northern rim of the atoll near Direction Island, at the north-eastern side of the lagoon around Port Refuge.

The boat crosses the lagoon from West Island to reach them, and they are conveniently paired with the lunchtime surface interval on the beach at Direction Island (eco toilets and shelters, no shops). Live-boat drops or moorings; no shore access.

Cocos has two seasons. The south-east trades blow steadily from roughly April/May to October, often 15–25 knots, which chops up the lagoon and pushes swell onto the eastern and southern outer reefs; divers are then kept to sheltered sites. The doldrum season (November to March/April) brings lighter, variable winds, flatter seas and the widest choice of outer-reef sites, and is the best time to dive, though it is also the tropical cyclone season and squalls pass through.

The northern-rim sites near Direction Island catch tidal flow through the passage at Port Refuge; the incoming tide brings clear ocean water and upwelling along the drop-off, the outgoing tide carries lagoon water out and lowers visibility. In strong south-east trades the lagoon crossing is choppy and wet but these sites are partly protected by the atoll; big northerly swell, uncommon, closes them.

Descend at the bommie at about 14 m, locate the two winches and follow the cables across the reef, then circle the bommie looking under ledges for lionfish and hiding fish. Watch the blue for grey reef sharks. Ascend on the bommie for the safety stop.

Cocos Dive (Dieter Gerhard, West Island, operating since 1990) is the only scuba operator on the islands and the only way to dive this site. It runs seasonal two-dive day trips with lunch and a surface interval on Direction Island, maximum 10 divers per trip; sites are chosen on the day according to wind, tide and diver experience. Trips book out well ahead and courses are currently suspended, so arrive certified.