Situated on the northern coast of the predator-free Tāwharanui Peninsula, the area has been closed to fishing since 1981 and was given marine reserve status in 2011.

The ecosystems within Tāwharanui Marine Reserve are healthier and in a more natural state than those outside its boundaries. The reserve is, however, influenced by the health of the marine environment outside its boundaries – it has no walls.

Larger-scale factors in the Hauraki Gulf such as changing climate patterns, urban development and overfishing affect the health of this marine reserve.