One Ton, also known as Jacobs Bommie, is listed by Oceanatik as a shore-entry dive to 30 m. Its description is of a bottom with many scattered rock formations covered in algae and corals, clean sand and abundant marine life. Oceanatik rates it for experienced divers and advises beginners to dive with experienced divers or instructors because currents can be unpredictable.

The two names hint at local history. 'Jacob's Bommie' suggests a person, possibly a local fisher or diver, and 'One Ton' may refer to an object or an event; Norfolk's coastal and fishing place names are often drawn from families and incidents, and the island's dive-site names were the subject of an academic study, but the origin of this one is not documented in the sources found.

The dive itself is a mix of sand and bommies. Scattered rock formations on clean sand attract fish from the surrounding open bottom, and the algae and corals on the rock support grazers and the predators that follow them. Norfolk's reef fish include wrasses, parrotfish, morwong, rock cod, moray eels and emperors, and stingrays rest on sand patches around the island.

A shore dive to 30 m with unpredictable currents is not a casual undertaking, particularly on an island with no chamber, so local guidance is strongly recommended. Confirm the entry point, the usual route and the depth before diving; depth fields other than the maximum are left blank.

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. Oceanatik lists One Ton (Jacobs Bommie) as a shore entry, but its location is not published.

Ask Norfolk Island Diving or the Visitor Information Centre in Burnt Pine for directions and whether it is best done from shore or by boat on the day.

Norfolk sits in the south-east trade wind belt. South-easterlies (strongest May–September) make the south coast and Kingston launch rough, and dives move to the north coast from Cascade; northerlies (more common in summer) do the reverse. Any swell over about 1.5–2 m on the exposed side stops the crane launch.

Visibility is typically 20–40 m. There is no stinger season; ex-tropical lows occasionally bring big seas in summer–autumn. Where this site sits relative to those exposures is not published – ask the operator.

With a local guide, descend over sand to the scattered rock formations and explore them, keeping depth within limits and watching for changes in current; return to the entry point with a safe gas reserve.

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).