Poor Knights Islands

The Poor Knights are the eroded remains of a volcano that erupted about eleven million years ago, sitting twenty-three kilometres off the Tutukaka coast in the path of the East Auckland Current, which carries warm subtropical water south. That current is why the diving here is what it is: species normally found in the tropics turn up alongside temperate ones, the walls drop into deep water covered in sponges and anemones, and the drowned rock is riddled with arches, tunnels and caves - including Rikoriko, one of the largest sea caves in the world by volume. The waters have been a marine reserve since 1981 and fully no-take since 1998. Landing on the islands themselves is not allowed at all: they are a nature reserve holding tuatara, giant weta and seabird colonies, and have been closed since 1981. So this is a boat trip and an in-water experience, weather permitting - and the crossing is often the part that decides the day.

What you actually see

• The subtropical fish - species carried south on the warm current.
• Rikoriko Cave - among the largest sea caves in the world.
• The arches and tunnels - the drowned volcanic rock.
• The walls - sponge and anemone cover dropping into deep water.

When to go

December to May, when the water is warmest and visibility best. Trips are cancelled in swell and wind - build a spare day into any plan built around this.

Honest expectations

You cannot land on the islands; this is boat and water only. The crossing can be rough and seasickness is common. Diving here needs certification and the deeper sites need experience; snorkel trips are the alternative.

Nearby

Tutukaka is the departure port; Matapouri and the Whangarei Heads are along the coast.