Goat Island — Leigh

There is no boat to catch and no schedule to keep, which is much of the appeal. Divers park above the bay, carry gear down to the sand and walk in, so the day is set by the drive rather than a departure time. Air fills and hire gear come from the dive shop at Leigh, a few minutes up the road. The University of Auckland's Leigh Marine Laboratory sits on the headland above the bay with a public marine discovery centre alongside it, and a good deal of the long-run monitoring of this coast has come off that site.

The channel between the beach and the island is narrow and shallow, and it is the forgiving half of the reserve: boulder reef and sand in the lee, swimmable across, diveable in most weather. The seaward side is the opposite. Northeasterly swell lands on it directly, so the archway and the outer pinnacle only go on settled days, and they are where the water actually moves. In between, kelp forest thins into sponge-covered rock as you drop.

The reserve's argument is legible on the rock itself. Researchers working out of Leigh have linked the return of large predators to the retreat of the urchin barrens that once stripped this coast — fewer grazing kina, more kelp — and a single dive can still cross from bare grazed stone into standing forest. It suits trainees, snorkellers and macro photographers, and anyone wanting a low-commitment dive close to a city. It does not suit divers after depth or structure, and the largest animal you are likely to meet is a stingray.

Summer weekends are the one real catch. The car park fills early, the shallows fill with snorkellers and school groups, and the entry zone gets stirred up as the day goes on. Going at first light, or on a weekday, changes the dive completely. Winter is colder and quieter, with more days when the seaward sites are unworkable, so the channel becomes the default rather than the warm-up.