The north coast of Lord Howe between North Head and Fishy Point is made of volcanic rock, and the sea has cut ocean caves into it. Pro Dive's description of this stretch mentions Twin Caves and a blowhole cave that 'penetrates in about 100 metres', with striking light effects in the cave systems. The area's overall depth range is given as 2–37 m.

Ocean caves like these are formed where the sea exploits weaknesses in the basalt, and they often connect to the surface through a blowhole, which lets light in and creates shafts and beams through the water. The walls are covered in encrusting corals and sponges, and caves at Lord Howe typically shelter crayfish, slipper lobsters and soldierfish. Outside the caves, Pro Dive notes large schools of kingfish and trevally along this coast.

The important thing to understand is the difference between the two features. Twin Caves are twin entrances best treated as a swim-through and cavern dive in daylight. The blowhole cave that runs about 100 m into the island is a much more serious proposition: a long overhead environment in which surge from the blowhole can move divers around. Recreational divers should enter only as far as the guide leads and within sight of daylight.

The north coast is sheltered in southerly and south-easterly weather, and that is when the caves are dived; any northerly swell makes them dangerous. This is a site for Advanced divers with good buoyancy who are comfortable in overheads. Its current use by operators should be confirmed.

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 North Passage, then turn east along the island's north coast between North Head and Fishy Point (below Malabar Hill). The run takes 10–15 minutes. The boat anchors on sand beside the reef or picks up a mooring where one is available.

Lord Howe sits in the path of the prevailing south-east to east trades and winter westerly fronts. The north coast between North Head and Fishy Point is protected from the prevailing south-east trades and from southerly and south-westerly swell, so it is one of the most reliable parts of the island and is dived in most weather. It is blown out by northerly and north-easterly winds and by north or north-west groundswell, which makes the caves and gutters surgy and pushes white water onto the cliffs.

The caves should be entered only when the swell is small. Visibility is usually 20–40 m. Diving is possible year-round, but the dive shop's main season runs September–June.

Guided only. Descend near the cave entrances and enter as a group behind the guide, staying in the daylight zone and keeping clear of the silt. Watch the light effects through the openings, then exit and finish the dive along the reef outside, where kingfish and trevally school, before ascending on the line.

Full penetration of the 100 m blowhole cave is a cave dive requiring cave training, a guideline and redundant lights; recreational divers should stay in the cavern zone.

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.