A chain of eroded volcanic islands 22 km off Tutukaka, Northland, warmed by the subtropical East Auckland Current. New Zealand's second marine reserve (1981, fully no-take since 1998) of arches, walls and the vast Rikoriko sea cave, rated by Jacques Cousteau among the world's best dives.
Destination info
Conditions, highlights, and the resident marine life.
Conditions
Water and air temperature across the year.
WaterAirDryShoulderWet
Description
The Poor Knights Islands are the eroded remains of ancient volcanoes about 22 km off the Tutukaka Coast of Northland, reached by a roughly 45-minute day-boat from Tutukaka Marina. The warm, subtropical East Auckland Current — water swept south from the Coral Sea — washes these temperate islands, carrying larval tropical fish that settle on the reefs and giving the reserve a marine community found almost nowhere else in New Zealand. The submerged volcanic geology is the draw: sheer walls, drop-offs, arches and the cavernous Rikoriko, among the largest sea caves on Earth by volume. Massive schools of blue and pink maomao swarm the arches alongside demoiselles, snapper, kingfish, moki and seven species of moray eel, while stingrays stack up in the caves over summer. Jacques Cousteau rated the islands among his top ten dives. Honest framing: this is cool, temperate diving — roughly 14–16°C in winter to 21–23°C in late summer — so a thick wetsuit or drysuit is essential, and the open, exposed approach can make surface conditions and the boat ride lumpy. Visibility runs 10–30 m, clearest May–September; the islands themselves are off-limits for landing to protect tuatara and seabird colonies. Two scuttled ex-Navy wrecks off Tutukaka, HMNZS Tui and HMNZS Waikato, are dived on the same trips but lie outside the reserve.
Highlights
What makes this dive worth the trip.
Part of the Poor Knights became New Zealand's second marine reserve in 1981; in October 1998 the last recreational-fishing provisions expired and the reserve became fully no-take, protected out to 800 m from shore. After full protection, surveys recorded large snapper at levels around 7.4 times higher than pre-reserve, with abundance and biomass climbing relative to fished control sites.
The islands are eroded ancient volcanoes whose submerged web of caves, tunnels, arches and cliffs led Jacques Cousteau to rate the Poor Knights among his top ten dive sites in the world — a ranking quoted across New Zealand tourism and dive sources.
Rikoriko Cave, on Aorangi Island, is widely considered the largest sea cave by volume in the world — a dome roughly 139 m long, 80 m wide and 35 m high (about 221,000 cubic metres), formed by a gas bubble in a lava flow around 15 million years ago. Its rounded acoustics are famous, and it is a popular shallow night dive.
Marine life
23 species you’re likely to encounter on a dive here.
Dive sites
6 signature sites at this destination.
Northern Arch
The signature dive of the Poor Knights — a large arch cutting through a rocky point at the northern end of Tawhiti Rahi, its top breaking the surface and its base dropping to about 37–38 m, with deeper water close by. The walls are crusted with sponges, anemones, hydroids and bryozoans, but the fish life is what divers remember: huge schools of blue and pink maomao, with snapper, kingfish, trevally and moki cruising through. Stingrays and eagle rays gather here in summer, and the depth and occasional current make it a more advanced dive than the sheltered arches.
5–38 madvancedDay boatModerateVisibility 10–30 m
Middle Arch
Like Northern Arch this tunnel cuts through a point, but it is far shallower — only about 15 m at its deepest — which makes for long, relaxed bottom times and forgiving conditions. The walls are splashed with encrusting sponges and the boulder-strewn floor shelters scorpionfish and moray eels. Schools of maomao, moki, demoiselle and colourful wrasses fill the arch, and the shallow depth and shelter make it a favourite for less-experienced divers and for second dives.
5–15 mbeginnerDay boatLightVisibility 10–30 m
Blue Maomao Arch
A shallow, sheltered archway named for the spectacle that fills it: divers are routinely overwhelmed by dense, shimmering schools of blue maomao packed wall to wall. The site is shallow and protected enough for all levels, and the silver-blue swarm against the sponge-encrusted rock is one of the most photographed scenes in the reserve. Stingrays and snapper are common, and the arch links to other shallow features for an easy, scenic dive.
3–16 mbeginnerDay boatLightVisibility 10–30 m
Rikoriko Cave
Among the largest sea caves on Earth by volume, this vast lava-bubble dome on Aorangi Island is big enough to motor a couple of dive boats inside. The entrance sits over 20 m deep and the back of the cave shallows to around 8 m, so it is an easy, shallow dive suited to any level. Inside, the dark walls and ceiling host black coral, encrusting life and macro subjects, making it a renowned night dive; the cave's rounded acoustics are legendary. A genuinely unusual environment rather than a fish-action site.
5–22 mbeginnerDay boatLightVisibility 10–25 m
HMNZS Waikato (off Tutukaka)
A 113 m Leander-class frigate decommissioned in 1988 and scuttled off Tutukaka on 25 November 2000 in a record sinking time of about 2 minutes 40 seconds. She lies in roughly 28 m of water with the shallowest structure only 12–14 m down, but two decades of storms have broken her into pieces, separated the bow and left her listing toward 45 degrees on the sand. A purpose-prepared wreck dive at diver-friendly depths — note it sits outside the marine reserve, not within it.
12–28 mintermediateDay boatModerateVisibility 8–20 m
HMNZS Tui (off Tutukaka)
A former US Navy oceanographic research vessel (originally the Charles H. Davis) leased to the Royal New Zealand Navy as HMNZS Tui and scuttled off Tutukaka on 20 February 1999. She rests in about 32 m of water and has broken into three main sections that are rapidly being colonised and merging with the reef. Dived on the same charters as the Waikato, it is a deeper, more advanced wreck and, like the Waikato, lies outside the Poor Knights Islands Marine Reserve.
18–32 madvancedDay boatModerateVisibility 8–20 m
Where to dive & stay
Local dive centers, resorts, and hotels.
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Verified dive centers, resorts, and hotels around Poor Knights Islands will list here — pricing, photos, and direct contact.
