We enjoyed being able to drive around and explore the island at our leisure versus booking a tour.
Waiheke Island is a fairly small island, however it is large enough that if you want to see it all you need to rent a car. There are many tours offered on the island that you can book, however we found them to be pricey and restrictive as you run on a tight schedule. We also saw several of these tours and they were buses loaded with people. Not our style.
So, we opted to rent a car and drive around for the long weekend. We rented from a lovely place, Waiheke Island Motors. We chose to rent here because the prices were the lowest and the reviews were the highest. They have cars starting at $42 USD per day which is a lot less expensive than some of the other rental places on the island.
I booked in advance, which I definitely recommend doing as they have a limited selection of vehicles so they book up fast. I let them know what time our ferry was arriving and once we arrived they were there waiting for us. So easy. They drove us to their property, had us sign some paperwork and off we went!
The staff was so friendly and laid back, so we really enjoyed renting from them. The most convenient part is that they let you leave your car parked at the ferry terminal at no charge. So, when it was time for us to leave we drove ourselves to the ferry, parked the car and left the keys in it. Then I just emailed them describing where in the parking lot I had left it, and they came and picked it up. It was so simple and convenient.