Little Organ – also called Organ Rock – is one of Norfolk's most characterful dives. Bounty Divers described 'the huge arch and several small caves and swim-throughs', with huge schools of drummer around the arch entrance, two resident boarfish and banded shrimp that pose for photographs. Explore TV's segment on Norfolk diving featured it: a big archway beneath the rock and an adjacent cave divers can swim through, at 21 m. Oceanatik describes a small rock formation east of Duncombe Bay with beautiful corals and marine life, a maximum of 24 m, mild currents, and rates it for experienced divers.

The arch is the centrepiece: large enough to swim through as a group, with the drummer school hanging in the entrance. The adjacent cave and small swim-throughs add interest, and the boarfish – large, deep-bodied fish with long snouts – are a special sighting, as they are usually found in cooler, deeper water. Banded coral shrimp in the crevices are a favourite macro subject.

There is some uncertainty over location. Oceanatik places Little Organ east of Duncombe Bay on the north coast, while Explore TV says the trip takes 10 minutes from Kingston Pier on the south coast. The boat launches from whichever pier suits the wind, and it is possible that the 10-minute figure refers to a launch from Cascade. The coordinates here are approximate and should be confirmed.

The dive suits Open Water divers with some experience, and Advanced divers will be more comfortable at the base. The caves and swim-throughs are short and open but should be avoided in surge. It is one of the dives Norfolk Island Diving shows visitors most often.

Norfolk Island is about 1,450 km east of Brisbane; flights run from Sydney and Brisbane (about 2.5 h; check the current carrier). A hire car is essential. Norfolk has no harbour: Norfolk Island Diving's open boat is lowered by crane from Kingston Pier (south coast) or Cascade Pier (north-east coast), whichever is in the lee of the day's wind, and divers board from the pier steps once it is in the water.

North-coast sites are normally reached from Cascade Pier (end of Cascade Road, about 10 minutes' drive from Burnt Pine): the boat runs north-west along the cliffs to the Duncombe Bay area below the Captain Cook Monument, roughly 15–25 minutes. The coast here is within or beside Norfolk Island National Park.

Norfolk's north coast, from Duncombe Bay west to Anson Bay, is in the lee of the prevailing south-east trade winds, so it is the most reliable part of the island for much of the year. It is exposed to northerly and north-westerly winds and swell, more common in summer, which break on the cliffs and pinnacles and cause strong surge. Anything over about 1.5 m of northerly swell closes the boat sites; the beaches need a flat day.

Visibility is typically 15–45 m and often best in winter. There is no stinger season.

Descend to the arch entrance, where the drummer school gathers, and swim through the arch. Explore the adjacent cave and small swim-throughs, look for the resident boarfish and banded shrimp, then circle the rock and ascend on its upper face.

Norfolk Island Diving (local instructor James and divemaster Mitch Graham) – small open boat craned in at Kingston or Cascade Pier depending on wind; runs part-time, mostly weekends, so book ahead by email (norfolkislanddiving@gmail.com).