Deacon's Delight is one of the named sites that Lord Howe's tourism body and Spacifica list among the island's standard dives, and Divernet gives a short description: a site to about 22 m with swim-throughs lined with soft purple coral. It lies in the northern Admiralty area.

Divernet's species list is notable for its big-animal interest. Galapagos reef sharks are the usual large visitor, blue-streak fusiliers school in the current, and harlequin tuskfish and clown triggerfish – two tropical species at the southern end of their range here – are on the reef. Divernet also records the occasional tiger shark, which is a reminder that Lord Howe is an oceanic island with open-ocean predators passing through; sightings are rare.

The swim-throughs are the structural highlight. Soft corals thrive where there is current and shade, and the purple soft coral lining the swim-throughs makes for good wide-angle photographs in Lord Howe's clear water. Around them the reef is a typical Admiralty mix of rock, hard coral and gorgonians with plenty of reef fish.

At 22 m maximum, the site suits Open Water divers comfortable with swim-throughs, though Advanced certification helps if the current is running. As with the other Admiralty sites, it is chosen when southerly winds put the northern islets in the lee, and it is exposed to north-east swell, which makes the swim-throughs surgy. Details of the exact position and route are not published; follow the guide's briefing. It is commonly paired with Rupert's Reef or Tenth of June on a morning double, since all three lie within a few minutes of each other in the Admiralty group.

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 to 18–22 m and work through the swim-throughs lined with purple soft coral, keeping an eye out in the blue for Galapagos sharks and blue-streak fusiliers. Return shallower along the reef top 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.