Things to do · Destination Guide
Wild kelp forests and predator free islands off the Coromandel coast
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For certified divers the Mercs pack a lot into a compact area: sheltered bays ideal for training, caverns and arches, walls plunging past 30 m and offshore pinnacles that draw kingfish, trevally and big schools of blue maomao. Dive Zone Whitianga and other local charter operators run day boats that choose sites based on swell and wind, so you can usually find a lee even when the forecast looks marginal. This is classic New Zealand temperate diving with a strong conservation story layered on top.
A large, mostly sheltered bay on the eastern side of Ahuahu with extensive kelp reef, rocky walls and sand patches that drop towards 30 m at the entrance.
On the northern side of the Mercs, The Cathedral combines a sheltered inner bay of sand and broken kelp with outer walls, boulders and pins that catch swell and current.
On Cuvier Island, often combined with extended Mercs and Aldermen trips, West Point offers clear blue water, steep reef and big fish potential when conditions and permits align, giving a taste of truly offshore New Zealand diving.
On the northwestern side of Great Mercury, The Book Case is an advanced wall dive with a near vertical face in the 25 m to 30 m range, frequent current and big fish potential.
An exposed pinnacle in open water, suited to experienced divers comfortable in strong current and blue water ascents.
Operator Checklist
Base yourself in Whitianga for easy access to Dive Zone Whitianga and other local charters that run day trips to Ahuahu and, in good weather, the outer Mercs and even Cuvier or the Aldermens. Summer weekends book out, so reserve boat spots and rental gear well ahead, especially around New Zealand public holidays. Bring your cert cards and logbook, and expect skippers to ask about recent cold water experience before putting you on advanced sites. Caulerpa rules mean you cannot take any marine life from the Great Mercury Island zone and must thoroughly wash and dry all gear between locations.
Conditions Fallback
Avoid