Warm mineral water has drawn travellers for more than two thousand years. These five natural baths range from an ancient Greek spa town on white travertine terraces to a Roman temple spring in England and a milky-blue lagoon in an Icelandic lava field.

White travertine terraces of Pamukkale, Turkey

Here is what makes each one special, the water temperature where it is known and the practical details for a visit.

1. Pamukkale and Hierapolis, Türkiye

Pamukkale, “cotton castle” in Turkish, lies in Denizli Province in south-western Türkiye. Its white terraces form as mineral-rich spring water reaches the surface and releases carbon dioxide, leaving calcium carbonate that hardens into travertine. The formation is about 2,700 metres long, 600 metres wide and 160 metres high, fed by 17 hot springs ranging from 35 °C to 100 °C.

On top sits Hierapolis, an ancient Greek city founded as a thermal spa in the early 2nd century BC; its name is usually read as “holy city”. Together they became the UNESCO World Heritage Site Hierapolis-Pamukkale in 1988. You can bathe in designated thermal pools, most famously Cleopatra’s Pool, where ancient marble columns lie under the warm water. Some terrace sections close in rotation so the travertine can regenerate.

2. Dalyan mud baths, Türkiye

Visitors at the mud baths of Dalyan, Turkey

Dalyan, whose name means “fishing weir”, is a river town in Muğla Province between Marmaris and Fethiye. It is known for its Lycian rock tombs, carved into the river cliffs around 400 BC, the ruins of ancient Kaunos a short boat ride across the water, and river boats that are the easiest way to reach the local sights.

Upstream, on the south-western shore of Lake Köyceğiz, the Sultaniye hot springs release sulphurous water at about 40 °C, and the spa there offers mud baths said to rejuvenate the skin. The mud-bath ritual is simple: coat yourself, let the mud dry in the sun, then wash it off. Archaeological finds suggest a sanctuary of the goddess Leto once stood nearby.

Nearby İztuzu Beach is a nesting ground for endangered loggerhead turtles, and it closes from 8 pm to 8 am between May and October.

3. Saturnia and the Cascate del Mulino, Italy

Pale terraced pools and flowing water at Cascate del Mulino near Saturnia
Pale terraced pools and flowing water at Cascate del Mulino near Saturnia.

Just outside the village of Saturnia, in the Maremma of southern Tuscany, warm water spills over pale limestone ledges at the Cascate del Mulino. The water rises from an underground source rich in sulphur and other minerals and stays at a steady 37 °C year-round. It has reportedly been used for minor ailments since Roman times.

Entry to the cascades is free, unlike the paid spa complex nearby. Arrive early to beat the crowds; locals bathe here even in midwinter. Bring water shoes, a towel and a bag for wet clothes, and leave soaps out of the water.

4. Bath, England: the Roman Baths and Thermae Bath Spa

Historic Roman Baths in the city of Bath, England

In Bath about 1,170,000 litres of hot water rise every day, heated deep underground to between 69 °C and 96 °C and reaching the baths at around 46 °C. The Romans built a temple to the goddess Sulis Minerva here between AD 60 and 70 and added the bathing complex over the next 300 years. More than a million people a year visit the Roman Baths and Pump Room.

You cannot swim in the Roman Baths: the water in the Great Bath is untreated. To bathe in the same spring water, go to Thermae Bath Spa, which treats it for safe bathing and has an open-air rooftop pool with views over the city. The minimum age is 16, and 18 for treatments. The spa also runs swim sessions in the historic Cross Bath.

5. Blue Lagoon, Iceland

Blue Lagoon geothermal spa in Iceland

The Blue Lagoon sits in a lava field on the Reykjanes Peninsula, about 5 km from Grindavík and 20 km from Keflavík International Airport. It is man-made: the water is runoff from the neighbouring Svartsengi geothermal power station, and its high silica content gives the milky blue colour and the soft white mud on the bottom. Bathing water averages 37–39 °C. The first bathing facilities opened in 1987.

Volcanic eruptions on the peninsula closed the lagoon several times in 2023 and 2024, and in November 2024 lava reached the site and destroyed its car park. Check the operator’s website for current status before booking. Our Blue Lagoon guide covers the experience in more detail.

Planning a thermal bath trip

Follow each venue’s bathing guidance, drink plenty of water, and ask a doctor first if you have a heart condition or are pregnant. Check age rules, changing facilities and whether non-bathers can join you.

For more ideas, see natural pools and places that are for viewing only, or the Aegean rock basin of Giola on the Greek island of Thassos. The natural swimming-pond feature looks at David Pagan Butler’s planted garden pools.

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