Fan Wall is one of the deeper northern-rim sites and the official Cocos tourism listing recommends it for more advanced divers. The range is 18–40 m, and it is described as having 'plenty to see on top and down the wall'. The reef top at 18 m is covered in healthy coral and busy with reef fish, and the wall falls into deeper blue water where the gorgonian fans that name the site grow.

At about 40 m there is a cave that the official listing notes is accessible to experts – a dive for those with deep training and experience, and only with the guide's agreement. Because the wall faces open water, the pelagic life is good: black trevally school off the face, sharks cruise the wall, and dogtooth tuna appear out of the blue. The combination of fans, big fish and depth gives the site a more serious feel than its neighbours Cannons and Two Ridges, which are only a short swim away, and it is a natural choice for experienced groups.

Depth planning is essential. The interesting parts are deep, no-decompression times at 30–40 m are short, and there is no recompression chamber on the islands, making conservative profiles more important than usual. Currents can run along the wall with the tide.

Divers new to deep diving should hold at 25–30 m and enjoy the fans and fish rather than aim for the cave. For photographers, the fans with trevally or a shark passing make strong wide-angle subjects. Details of the cave's size and extent are not published; penetration beyond daylight should not be attempted.

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 on the reef top at about 18 m, then drop down the wall to the gorgonian fans at 25–30 m. Divers with deep experience and the guide's approval may visit the cave at about 40 m briefly; everyone else holds shallower. Ascend along the wall, finish on the reef top and do an extended safety stop.

Cave at about 40 m is at the recreational limit; air only unless Cocos Dive confirms nitrox. Conservative gradient and extended safety stops advised given aeromedical evacuation distance.

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.