The Triangle is paired with Gower Pinnacle in Pro Dive's description of Lord Howe's southern deep sites, and the two share the same account: a plateau starting in 20 m, an escarpment, a platform at 32 m and rocky canyons past 40 m. Whether that describes one structure or two adjacent ones is not clear from the source, so The Triangle is kept as its own entry, as in the first pass.

The fish life described for the pair is some of the best on the island: sharks, a school of about 30 spangled emperor, huge kingfish that followed divers throughout the dive, Meredith's angelfish, conspicuous angelfish and high-fin coralfish. Black coral trees grow on the escarpment. Kingfish in particular reach a large size here because the whole island is a marine park.

The southern end of Lord Howe beneath Mt Gower is the most exposed part of the island, taking the south-east trades and southerly swell head-on, so the Triangle is dived only on calm days or in northerly weather. The run from the lagoon is roughly half an hour.

Because most of the interest is below 20 m and the canyons go past 40 m, this is a site for deep-trained, experienced divers with careful gas planning. Divers who want to stay shallower can remain on the plateau. Its exact position and profile are not published separately, so the figures here follow Pro Dive's shared description. Confirm with the dive shop whether it is currently dived. If it is, expect it to be offered on the same calm-weather days as Gower Pinnacle.

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 leave the lagoon through Erscott's Passage at its southern end, then run south along the western coast beneath Mt Lidgbird and Mt Gower. The southern sites are the longest runs of the regular dives, roughly 25–30 minutes, and are done only when the sea allows.

Lord Howe sits in the path of the prevailing south-east to east trades and winter westerly fronts. The southern end of the island below Mt Gower is fully exposed to the south-east trades and to southerly and south-westerly swell, which is why the southern sites are dived only on calm days or in northerly to north-easterly winds. More than about 1.5 m of southerly swell or 15 knots of south-easterly closes them.

Current can run around Gower Island and the pinnacles. February–May usually brings the most suitable days; winter trips are uncommon.

Descend to the plateau at about 20 m and follow the escarpment and canyons as depth and gas allow, watching for kingfish and spangled emperor. Ascend along the reef to the line for the safety stop.

Below 40 m requires technical training; nitrox useful on the plateau.

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.