On the day our planned trip to Motukaraka rolls around, the men bail — one with a cold and the other to work. It's left to me and my sister to take our collective brood to what we've promised is a kind of treasure island — albeit one you can walk to.
Known to locals as Flat Island, Motukaraka sits just off the coast of Beachlands on the Pohutukawa Coast. The island has a tragic past: once a fortified pa and home to several hundred people, it was invaded and its community massacred in the early 19th century. Uninhabited since then, it's been briefly farmed by an early settler, was ravaged by fire in 1965 and is now a serene reserve.
Walking becomes possible at low tide — the island is connected to the mainland by a submerged sandbar that hooks around from Pine Harbour Marina. Between mid and low tide, the sandbar is exposed, sweeping towards the island's cliffs — a cockle-shell highway that begs exploration.
It's possible to start from the boardwalk that leads east from Pine Harbour Marina — a great idea on Saturday mornings when the marina's Fresh Market sells bread and gourmet provisions — but we start from Puriri Rd, just past Beachlands township. We park beside Puriri Reserve, cross the reserve and take the pohutukawa-shaded steps to the bottom of the cliff. It's a descent to another world.
The island glitters less than 500m away, but a sense of magic belies its proximity. We feel thrust into the turquoise water of the gulf, adrift on a giant raft. I'd been planning to tell the older children, who are between 5 and 8, to keep an eye out for cockles, but they're gone in seconds, fanning out across the mudflats. As we walk they weave back and forth excitedly, waving wet strands of seaweed, cupping the odd crab and regaling us with high-pitched descriptions of sea anemones.
Even without a tip-off about cockles the children soon spy them poking out of the soft mud. Having heard that the beds are only just regenerating after years of ill-planned marina dredging and dumping, we keep just a handful of the bigger ones to cook for afternoon tea.
When we reach the island, the children are captivated by "a real live shipwreck" — the hull of a small yacht washed up on the beach. It's perfect for playing boats in and lies next to a hulking dead pohutukawa, so there's clambering and swinging between the two. When afternoon tea starts to appeal we head around the island to get out of the wind, perching on rocks to boil a billy. Murphy's Law prevails and the gas canister runs out just as the water's coming to the boil, so the shellfish have to wait 'til we get home — but we've got bread and jam to tuck into.
If there had been time, we'd have circumnavigated the island — the sandstone cliffs are full of caves and there's a shag colony around the far side — but that will have to wait for another day.
When we turn for home, water has covered the sandbar and it's a splashier walk than we'd anticipated. The tide races towards us from both sides and the kids are knee-deep — but no one's complaining. This has been an outing with that hint of unpredictability that marks real adventure.
• Park beside Puriri Reserve, on the corner of Puriri Rd and Hawke Rd, Beachlands. This is a loop walk, you'll return to the place you parked the car. Accessible on foot for the three hours either side of low tide, but you're safest to start the walk at least an hour before low tide to allow time to circumnavigate the island.
• Ferries run 15 times daily between downtown Auckland and Pine Harbour Marina, where you can also start the walk — service runs only Monday — Friday, no weekend service.
• Pine Harbour Fresh Markets, Saturdays from 8am-12 noon. Pine Harbour Marina, 190 Jack Lachlan Drive, Beachlands. A French-styled market selling fresh local food and European gourmet ingredients.