Nigel Marsh logged Roach Wall as one of a trio of Lord Howe dives – with Sugarloaf and Malabar Landslide – that gave 30 m visibility, Galapagos sharks, fusiliers, drummer and rare angelfish. It is the steepest face of Roach Island in the Admiralty Islets and is dived separately from the boulder and swim-through sites on the island's gentler sides.

Diveplanit describes the Admiralty drop-offs as walls of coral, and on Roach Wall that means a near-vertical face with hard corals, gorgonian fans and encrusting sponges, broken by ledges and small overhangs. The wall drops into the 20s and beyond, and the depth to aim for depends on the day's current and the group's experience.

The open water off the wall is the main attraction. Galapagos sharks are the most reliable large animal at Lord Howe and cruise along the face, while fusiliers and drummer school in the current. Kingfish and trevally move through, and large pelagic fish are more likely here than on the lagoon-side sites because the Admiralty Islets are washed more directly by the Coral Sea current. On the wall itself, look under ledges for the subtropical angelfish Lord Howe is known for, morays, lionfish and nudibranchs.

Wall dives on the Admiralty Islets require good buoyancy control, and the current can pick up along the face. It is best suited to Advanced divers, and to Open Water divers only in calm conditions with a guide. As with all the Admiralty sites, it is chosen when the wind has some south in it and the north-east swell is small. Detail on the exact profile is limited, so follow the guide's briefing.

Lord Howe is reached only by air: QantasLink flies from Sydney daily (about 1 h 50 min), with Brisbane and seasonal Port Macquarie services. Accommodation must be booked before flights (visitor numbers are capped at about 400) and the checked-baggage limit is 14 kg, so most divers hire gear on the island. Dive Lord Howe's shop is at 2 Lagoon Road beside the Lagoon Beach boatsheds; most lodges transfer divers or it is a short bike ride.

Divers board the boat, which is moored in the lagoon, and exit the lagoon through North Passage, then run north-east around North Head to the Admiralty Islets, a group of seven rocky islets a few hundred metres to about 1.5 km off the island's north-east tip. The trip takes about 20 minutes. The boat anchors on sand or a small reef close to the site or runs live if there is current.

Lord Howe sits in the path of the prevailing south-east to east trades and winter westerly fronts. The Admiralty Islets are exposed to north-east and easterly swell and to northerly winds, which blow them out; they come into their own in south-westerly to southerly winds, when the island shelters them and the southern and western sites are rough. A 1.5 m swell from the north-east makes the shallower gutters surgy, and a lump above about 2 m stops the trip.

The Coral Sea current washes these islets more than other sites, so currents can pick up, especially on the outer edges. Visibility is typically 30–40 m. Best months are February–May; winter westerlies are fine here if the swell is down.

Descend near the wall and drop to 20–25 m, then swim along the face with it on one shoulder, watching the blue for Galapagos sharks and fusilier schools. Turn at half air, rise to 10–15 m for the return and finish near the island's shallower boulders.

Dive Lord Howe (PADI 5-star, 2 Lagoon Road) – morning double boat dives daily in season, afternoon single dives on demand; site chosen on the day by wind and swell. Howea Divers has also advertised dives here.