Ferry from Auckland to Great Barrier Island
While you have a lot of day tours to Great Barrier Island you also can just hop on the ferry to Great Barrier Island and see for yourself the things you can do on this lovely but remote island. It's also possible to add a car to this crossing. Make sure to bring your own food to this crossing as the prices for food are expensive and the quality of the food is average.
Ps. When you are lucky you are able to see dolphins next to the ferry!