The Palea Kameni hot springs swim, in plain terms
The most-asked stop on the route, and the one most often misdescribed. It is a swim in warm rust-coloured seawater, not a spa. You go in off the stern and swim about 50 metres to reach it.
€100 per person · 10:00 - 15:00 · Shared seats
The hot springs are in Agios Nikolaos bay on Palea Kameni. You reach them by swimming from the boat, roughly 50 metres of cold open water before it turns warm. The water runs ochre with iron oxide, is published at about 30 to 35 °C, and it stains pale swimwear permanently. Wear something dark.
This is the stop guests ask about more than any other, and the one they arrive with the wrong picture of. There is no pool, no jetty, no attendant and no towel rail. There is a small bay on an uninhabited island, and the sea in it is the colour of rust.
Stop 7 of 7 on the Semi-private day cruise
What to expect in the water
| What actually happens | |
|---|---|
| What to wear | A dark swimsuit, or an old one. Not white, not pastel, not the one you like most. Water shoes help if you have them — the bottom close to the shore is rough volcanic rock. |
| How you get in | Off the stern of the boat, into deep cool water, and you swim. The bay has no harbour and shallows towards the chapel, so a catamaran our size cannot go in. It is roughly 50 metres to the warm patch. |
| What it looks like | Yellow-green through to rust-orange, and opaque enough that you cannot see your own feet. The colour is iron oxide, with sulphur and manganese, seeping up from vents under the seabed. |
| How warm it is | Published figures put the warm patches at about 30 to 35 °C, against an Aegean sea of roughly 20 to 25 °C depending on the month. That is a tourism figure, not an instrument reading. Warm, not hot. |
| How long you get | Ten to twenty minutes in the water, when the sea allows the stop at all. The grill is already working at the volcano anchorage next door, so lunch follows soon after you are back up the ladder. |
| What it does to fabric | The iron oxidises and binds to the fibres, which is the same chemistry as rust on a white shirt. First-hand accounts report orange-brown marks surviving repeated washes. Dark, old or synthetic swimwear survives best. |
| Afterwards | Rinse skin, hair and swimwear as soon as you can, and wash the swimsuit that evening. The longer the minerals sit in the fabric, the better they stay put. |
| Who should stay aboard | Weak swimmers and very young children. There is no shallow entry and nowhere to stand until you are almost at the shore. Nobody minds if you sit it out, and several people do on any given cruise. |
There is a smell of sulphur. It is not strong, but it is there, and it is the thing people notice second, after the colour.
What the swim is actually like
The part nobody warns you about is the first thirty seconds. You go in off the stern into open caldera water, somewhere between 20 and 25 °C depending on the month, and after an hour on a hot deck it feels colder than that. Then you swim, and nothing is warm for most of the way.
Then there is a line. The water changes colour and you cross into the plume. It is less a gradient than a boundary, and the boundary moves with the wind and the swell, so two people ten minutes apart get different swims.
Warm, not hot. If you were expecting a thermal bath, that is the sentence to carry with you. In August, when the sea is already close to 25 °C, some guests barely register the change. In May or October the contrast is obvious.
Near the chapel it shallows to about chest depth over rough rock. Most people stand there for a while, then swim back. It is a swim with a curiosity at the end of it, not a soak.
The staining is permanent often enough that we say it flatly. White comes back cream or orange and does not recover. The same goes for pale board shorts and for a light rash vest. Pack something dark for this stop and keep the good swimsuit for the other three.
The longer version, including what to do if you did wear the white one, is in the hot springs swimsuit rule.
Why the boat cannot go closer
The honest answer is water depth, not laziness. The caldera floor lies 300 to 400 m down across most of its area and the walls fall away almost vertically from the shoreline, so there is nowhere to lie except close in.
Close in, Agios Nikolaos bay shallows over rock, with no harbour and no jetty on the whole island. A catamaran of ours drawing what it draws has no business in there.
So we lie off and you swim. Every boat on the caldera does the same thing, including the big volcano boats. If somebody promises to take you into the bay, ask them how.
The stop is on all five of our catamaran cruises when the sea permits — the cove takes wind badly, so treat it as the day's bonus rather than its promise. When it runs, it comes on the way home from the Fira panorama, around 14:05 on a 10:00 departure, as the boat threads the channel between the two Kameni islands.
The island itself
Palea Kameni means the old burnt island. It is about 0.5 km², built by eruptions between 197 BC and AD 47, with a submarine explosive eruption in AD 726. In antiquity it was called Hiera.
It is pumice and dacite lava, black craters, thin succulent scrub and a herd of goats. The bay takes its name from the small chapel of Agios Nikolaos on the shore. Almost nobody lives there.
Its neighbour, Nea Kameni, is the younger island with the crater walk on it. The two are often described as one place. They are not, and only one of them has the warm water.
Bring the dark swimsuit
The hot springs are on every one of our catamaran cruises, sea state permitting. Five hours, €100 per person, lunch cooked on deck while you swim.
Call the harbour office+30 698 977 1888
Common questions
Are the Santorini hot springs actually hot?
Warm rather than hot. Published figures put the water at about 30 to 35 °C where the springs come up, against a surrounding sea of roughly 20 to 25 °C. That is a tourism figure and not an instrument reading. In August the contrast is mild; in May or October it is far more obvious.
Do Santorini's hot springs stain your clothes?
Yes, and often permanently. The iron and sulphur in the water leave orange-brown marks on pale swimwear, and first-hand accounts report the marks surviving repeated washing. Wear something dark or old, then rinse and wash it the same evening. The sooner it is washed, the less the minerals bind.
What should I wear to the hot springs?
A dark or older swimsuit you do not mind discolouring. Leave the white bikini and the pale board shorts in the room. Water shoes are worth having, because the bottom near the shore is rough volcanic rock, and a rash vest helps for the open-water swim out and back.
How deep is the water at the hot springs?
Shallow close to the shore, commonly described as chest-deep, but deep where the boats lie. That is the part that matters: you enter in deep water and swim in. There is no shallow entry and nothing to stand on for most of the way, so weak swimmers should stay aboard.
Can you visit the hot springs without a tour?
Not realistically. Palea Kameni is uninhabited, with no ferry, no road and no path, so reaching Agios Nikolaos bay means a boat: a shared cruise, a private charter, or your own vessel. There is nothing waiting when you arrive either, no facilities, no shade and no fresh water.
How long do you get in the hot springs?
Twenty to thirty minutes in the water is normal on our cruises, which is about what most people want. The grill is lit while you swim, so you come back to lunch. If the wind is up the captain may shorten the stop or skip it, and that decision is made on the water.
Santorini Boat Tour - Water Taxi is a catamaran cruise and water taxi operator based in Fira, Santorini.
Updated August 2026