The hills south of Pauanui are the remnants of a massive rhyolite dome that formed 7-8 million years ago. On the coast there are interesting features such as columnar lava outcrops at various stages of erosion, in places forming pillars and smooth pavement-like platforms. Also good views from Pauanui Trig, a steep 50 mn walk from the southern end of the beach. Two separate springs release hot water through the sand, at temperatures of 60 and 64 degrees C respectively. This is a great place to get a warm bath, especially in winter.
Hot water is accessible at mid to low tide only.
It is thought that the water rises along a fault from a reservoir of superheated water located several kilometres below the surface. This area is both extremely scenic, and has very interesting coastal volcanic features. The best known is Cathedral Cove, north of Hahei. There a magnificent arch through the headland connects two white sand beaches. The main one is especially large and impressive.