Emerald Lakes

After hours of walking across grey ash, black lava and the rust-coloured slopes of Red Crater, the Emerald Lakes come as a shock of colour. Three small pools lie cupped in old explosion craters high on Mount Tongariro, in the central North Island of New Zealand, at about 1,725 metres above sea level, and their water is a brilliant green that looks almost artificial against the barren volcanic ground. Their Māori name, Ngā Rotopounamu, means the greenstone lakes, and the comparison is exact.

The colour is chemistry. The craters belong to a small chain of vents blasted open by gas and steam eruptions within the last 1,800 years, and they are fed by water that seeps through the surrounding volcanic rock and picks up dissolved minerals, among them calcium carbonate, that tint the pools. Steam vents on the slope above fill the air with a sulphurous smell, a reminder that this is an active volcanic landscape. The contrast is what makes the view: the lakes are small, but seen from above, with the red-black rim of the crater behind, they are the signature view of the whole crossing.

These waters are also sacred. All the waterways of Tongariro and its companion peaks Ngauruhoe and Ruapehu are sacred to the local iwi, Ngāti Hikairo ki Tongariro of Ngāti Tūwharetoa, and visitors are asked not to touch or enter the lakes. That relationship is part of why Tongariro, New Zealand's first national park, established in 1894, was also recognised as a World Heritage site for its cultural as well as natural values in 1993. Conservation work continues here too: since 2019 the Department of Conservation has fought an invasive aquatic weed in the lakes and reduced it to undetectable levels.

Getting there

The lakes are reached only on foot, on the Tongariro Alpine Crossing, a one-way day walk across the volcano that climbs from the Mangatepōpō valley (1,120 m) to the high point at Red Crater (1,886 m) and descends past the Emerald Lakes and Blue Lake to the Ketetahi road end (760 m); allow most of a day. Because it does not return to its start, most walkers use shuttle services from nearby towns, and parking at Mangatepōpō is not available in summer. The nearest town is Taupō, about 62 km away, and Taupō Airport (TUO) is about 58 km away. The weather on the crossing changes quickly, and the route is exposed alpine terrain.