Introduction to Waiheke Island: Waiheke Island (Waiheke) is the most populated island among the many islands in the Hauraki Gulf of New Zealand. It is composed of farms, forests, beaches, vineyards and olive trees. Picturesque views. Popular island activities include swimming, golfing, horseback riding or kayaking. At the easternmost end of the island are rocky slopes, and a large number of underground tunnels left over from World War II can be visited.