Queenstown's Onsen Hot Pools look out over the Shotover River and surrounding mountain range. Photo / Supplied
For centuries, a soak in thermal waters has been recognised as therapeutic, cleansing and healing. Cultures all over the world have used warm-water bathing as part of their holistic health remedies; here, Māori have long-held beliefs about the healing power of New Zealand's geothermally heated springs. Mineral water tends to be high in silica, which is known to help soothe irritated skin.
But you don't have to find a geothermal hot spot to benefit from warm-water therapy - any immersion or bathing experience that heats the body is said to be beneficial. Taking a bath can improve heart health, help you breathe easier, benefit the nervous system, joints and muscles, and even improve immunity.
In New Zealand, we're spoilt for choice when it comes to thermal bathing - both natural springs and artificially heated outdoor hot baths nestled in nature's finest scenes.
• Check with your doctor first if you have underlying health or heart conditions
Polynesian Spa, Rotorua
Rotorua is arguably the original home of New Zealand's natural hot springs, given how geothermally active the region is. Rotorua's Polynesian Spa is based at the site of the city's first bathing building, which was established in the 1800s, therefore claiming the title as New Zealand's original geothermal bathing experience. Some parts of the facility have been recognised for their historic importance by the New Zealand Historic Places Trust.
There are 28 pools fed from two natural mineral springs, acidic and alkaline, as well as spa therapies to complete the experience.
The Lost Spring, Coromandel
The Coromandel is most widely known by Aucklanders for its thermal area at Hot Water Beach. But in Whitianga there's another mineral springs complex, The Lost Spring.
Surrounded by native bush in a Pacific Island-themed setting, the pools from The Lost Spring range in temperatures from 32C to 41C. The water is said to come through a small crack in the bedrock, fossilised after more than 16,000 years underground. The water source was considered lost - hence the name - and rediscovered in 1989.
If you want a unique bathing perspective, Wairua Lodge offers guests a treetop bathhouse. Sheltered within a rainforest, guests can enjoy a candlelit soak in the bubble bath while sipping a glass of champagne. The lodge also has an outdoor spa pool, the "night-sky" spa pool, where guests can relax in the tub while stargazing. There is very little light pollution, making for a romantic starry night.
Nearly halfway between Rotorua and Taupō is a beautiful little hot pools complex at Waikite Valley. It might not have the luxury of Rotorua's Polynesian Spa, but you can bet your bottom dollar there'll be fewer people and a good chance of soaking solo.
The pools are fuelled by Te Manaroa Spring, which discharges thousands of litres of geothermal energy into the Otamakokore Stream, making it the largest single source of geothermal water in the country. The water is unfiltered from the spring but is cooled before entering the pools.
There are several bathing pools as well as private tubs where you can control the temperature of the water, while surrounded by native bush views across the geothermal activity.
The Tokaanu Thermal Pools are on the edge of Lake Taupō, in an area historically significant to local Māori, who have used the geothermal resources of this area for cooking and bathing for generations, and still continue to do so today. The waters are considered a taonga of the Ngāti Kurauia people.
The thermal pools range in temperature from 39C to 41C, and there's also a large public chlorinated pool heated to about 36C to 38C. The pools are a simple but delightful escape; they're relatively inexpensive and there's a beautiful walk in the surrounding area around mud pools and steam vents. And you can see rainbow trout in a nearby stream - which is a cold stream, in case you had images of fried trout.
If starry nights and alpine views are your thing, a soak in the Tekapo hot springs will make your soul sing. While the water isn't geothermally heated, it is pure and comes from an underground source near Tekapo. The temperatures of the pools range from 36.5C to 38.5C.
The pools are 720m above sea level, with expansive views in the daytime out to Lake Tekapo and the surrounding Mackenzie Region, or the internationally renowned Aoraki Mackenzie International Dark Sky Reserve at night.
The three pools are named and shaped after the three lakes in the region - Ohau, Pukaki and Tekapo - with a surrounding landscape of alpine plants and trees, greywacke boulders and schist rocks.
For another alpine bathing retreat, try the Hot Tubs in Omarama, on the Omarama to Twizel section of State Highway 8 in southern Canterbury. The region is known for fishing, tramping and hunting so the hot tubs are an ideal spot to relax and unwind after a day in the outdoors.
The tubs are filled with fresh mountain water for each use, then heated by a wood fire, with no chemicals added. The temperature of the water can also be adjusted. The complex is surrounded by the high country tussocks of the upper Waitaki/Mackenzie Country, and you'll feel wonderfully isolated.
The Hanmer hot pools are part of the resort town of Hanmer Springs, practically a South Island institution, and a popular day trip for Cantabrians. This large complex, 90 minutes north of Christchurch, has 22 outdoor thermal pools as well as private pools, sauna and steam rooms.
Hanmer Springs markets itself as bathing in thermal water "173 years in the making". The water starts as snow and rain on the nearby mountains before seeping into greywacke basement rock, resting two kilometres underground where it is warmed by the Earth's core.
Surrounded by mountains of the South Island high country, it's especially picturesque in the winter after a snowfall.
Te Aroha Mineral Spas are also known as hot soda springs, as some of the water is naturally infused with sodium bicarbonate underground. The wooden tubs sit at the foot of Mt Te Aroha, the mountain that has made the area famous. Behind the spa building, you can wait and watch the world's only natural hot soda water geyser, Mokena Geyser, erupt.
Te Aroha has a long history and was once considered the most popular spa town in New Zealand. Some of the Victorian and Edwardian-era bathhouses have been refurbished for a glimpse into a bygone age.
The site was originally used by travelling Māori pounamu traders, coming from the west coast, as a place of rest and rehabilitation, especially after tribal battles.
The baths became popular among European settlers, who expanded the complex, and was a popular place for holistic medicinal treatment following World War I and II.
Not to be confused with Hot Water Beach in the Coromandel, Te Rata Bay's Hot Water Beach is on the edge of Lake Tarawera and is a pristine escape with a bit of DIY attitude required.
Part of the Rotorua Geothermal System, a hot spring trickles into Lake Tarawera, which heats up the sand on this little part of the lake's edge. It can heat up to 86C, which is hot enough to cook a hāngī.
Bring a tent to stay the night and a little shovel to dig your own hot pool on the beach.
Queenstown's Onsen Hot Pools are among the most widely photographed hot baths in New Zealand. And there's a reason for all those faceless portraits, backs to the camera, half immersed in the cedar hot pools, looking out to the incredible Queenstown landscape and overlooking the Shotover River.
The private tubs are beautiful at any time of day, year-round, but a candlelit evening soak looking out to the starry sky is a tranquil escape and contrast to the usual adventurous spirit of Queenstown.