Sugarloaf is the largest of the seven Admiralty Islets and a landmark for the northern dive sites – McFadyen locates Noddy and Shearwater islands by reference to it. Nigel Marsh grouped it with Malabar Landslide and Roach Wall as dives with 30 m visibility, Galapagos sharks, fusiliers, drummer and rare angelfish, and Diveplanit's survey of the Admiralty Islands describes steep drop-offs presented as walls of coral, bommies and large boulders, with swim-throughs where the islands meet below the surface.

Around Sugarloaf that means a mix of steep rock faces and boulder slopes dropping to sand in the 20s and deeper on the exposed side. The rock carries hard coral and gorgonian fans, and the boulders give shelter to morays, lionfish (including juveniles), tasselled flathead and painted morwong. Blue nudibranchs and dusky hydroids are among the macro life Diveplanit recorded around the islets.

The open-water side is where the bigger fish are. Galapagos sharks patrol the edges, fusiliers stream past in the current, and drummer school in the surge zone. The 'rare angelfish' Marsh mentions are the subtropical species that Lord Howe is known for, such as the conspicuous and half-banded angelfish.

The dive varies a lot with the side chosen and the conditions, from a sheltered boulder slope to an exposed wall. Operators pick the side in the lee on the day. It suits Open Water divers on calm days and is better for Advanced divers when there is current or when the wall side is dived. Being only about 20 minutes from the lagoon, it is a regular part of the Admiralty rotation.

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.

Anchor in the lee of the island. Follow the wall or boulder slope at 15–20 m with the island on one shoulder, looking out into the blue for Galapagos sharks and schooling fusiliers, and into the boulders for angelfish. Turn at half air and return shallower along the island to the anchor for the safety stop.

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.