Tenth of June is one of the best-known dives in the Admiralty Islets and one of the few Lord Howe sites operators list by name. Pro Dive's description is of a deep plateau at 24–36 m with swim-throughs, gutters, tunnels and vertical walls, and Divernet describes a reef with a smaller pinnacle rising close to the surface. Diveplanit lists a '10 June Bombira' among the Admiralty sites, and the island tourism site lists both Tenth of June and Tenth of June Deep.

The Admiralty Islets are washed more directly by the Coral Sea current than the rest of the island, and that shows here. The walls carry extensive soft corals, gorgonian fans and black coral trees, and Pro Dive records black cod up to 180 kg sheltering in the tunnels – a protected species that has become a signature of Lord Howe. Japanese boarfish, a striking deep-bodied fish found around Lord Howe and northern New Zealand, hang under ledges, and the gutters funnel trevally, drummer and other pelagic fish past divers.

On the smaller scale, look for egg cowries on the soft corals, Spanish dancers and other nudibranchs on the walls, and the Lord Howe tricolour fairy basslet around the reef edges. Large silver trevally and unicornfish are common.

The structure gives a lot of variety for one dive: a pinnacle top shallow enough for a relaxed safety stop, a plateau with swim-throughs in the low 20s, and walls that go past 30 m for those qualified to go deeper. It is an intermediate dive in normal conditions and advanced when the current runs, and the depth range means Advanced Open Water is the sensible minimum. It is dived when the wind has any south in it.

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 the line onto the plateau at about 20–24 m. Circle the pinnacle through the gutters and swim-throughs, looking into the tunnels for black cod and along the walls for Japanese boarfish and gorgonians. Divers wanting depth can drop to the deeper plateau edge (the 'Tenth of June Deep' variant) before working back up.

Finish around the shallow top of the pinnacle, which holds drummer and trevally, 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.