Meet the site
Cooks Arch is one of Norfolk's signature boat dives. Oceanatik describes 'a beautiful rock formation raising to 12 meters above surface and drops down to 21 meters below the surface', a pinnacle that intersects a reef system with multiple crevices and nearby caves, and an arch divers can swim through while looking at the surrounding coral and marine life. The Marine Life Network places it in Duncombe Bay, with rock walls from 12 to 21 m and abundant marine life.
The name links it to Captain James Cook, who sighted and landed on Norfolk Island in October 1774 during his second voyage; the Captain Cook Monument stands on the cliffs above Duncombe Bay.
The arch is the highlight. Swim-through arches are a feature of the north coast – Turtle Arch, Little Organ and Policemans Helmet are nearby – and at Cooks Arch the structure is large enough for a relaxed passage, with light coming in from both sides. The rock walls and crevices are covered in corals, sponges and fans, and Oceanatik describes an excellent display of marine life. Norfolk's reef fauna includes drummer, sweep, wrasse, butterflyfish, groper, morwong, rock cod and moray eels, and kingfish and trevally hang around the pinnacle.
Oceanatik rates the dive suitable for beginners, and the maximum depth of 21 m keeps it within Open Water range. The north coast is sheltered from the prevailing south-east trades, but northerly swell creates surge in the arch and caves, which should then be avoided. The boat usually launches from Cascade Pier. Coordinates are approximate for Duncombe Bay.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Cooks Arch is recorded as Pinnacle/Bommie in Norfolk Island. The listed access is boat (day trip). Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Current and timing
- Ask how the operator assesses the current window for the actual route. Historical tide notes are not a departure instruction.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
- Overhead environments
- Ask whether the plan stays entirely in open water. A wreck or cave listing is not permission or training to enter.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Cooks Arch suitable for my certification?
The record lists Advanced Open Water. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Cooks Arch through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Corals, sponges, sea fans, drummer, sweep, wrasse, butterflyfish, groper, morwong, rock cod, morays, kingfish, trevally
Location
A rock formation rising 12 m above the sea in Duncombe Bay on the north coast, with an arch, crevices and nearby caves to 21 m.
Facilities nearby
Departure from Cascade Pier (crane launch).
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
oceanatik.commarinelife.org.auoceanatik.comRecord updated 27 Sept 2026. Source claims are being reviewed.