From the journal

Swimming in the hot springs: what it is actually like

8 min read

What you get at the Santorini hot springs is a cold open-water swim with warm patches in it. You go in from the boat, because the bay is too shallow to enter under power. The water runs ochre from iron oxide, smells faintly of sulphur, and stains pale swimwear permanently.

This is the most over-promised stop in Santorini, and the gap between the brochure and the bay is where the disappointment lives. So here is the honest version, written by people who watch fifteen guests a day form an opinion about it.

Managing your expectations is the entire job of this article. Everything in it is a reason to go anyway.

Where it is and why the boat stops where it does

The springs discharge into Agios Nikolaos bay on Palea Kameni, the older of the two volcanic islands in the middle of the caldera.

Palea Kameni means old burnt island. It is 0.5 km² of pumice and dark lava with a handful of goats, one small chapel and, on the record, essentially one resident. It has no good harbour, and the bay itself shallows fast over rough volcanic rock.

So the boat lies off in deep water and you swim in. That is not laziness and it is not a shortcut. There is nowhere to tie up, the caldera outside the bay is hundreds of metres deep, and the inside is too shallow and too rocky to take a hull with fifteen people on it.

Community sources put the swim at roughly 30 to 50 m from a typical anchorage. We have not measured it from ours, so treat that as the market's figure rather than ours. Whatever the exact distance, it is open water and it is properly cold at the start.

The numbers

What people expect, against what it is

Nothing in the right-hand column is a complaint. It is just the thing itself.

	What people arrive expecting	What it actually is
The temperature	A hot tub. Something you lower yourself into and go quiet.	Published at roughly 30 to 35 °C where the springs come up — a tourism figure, not an instrument reading. Against an August sea of about 24.5 °C, that is noticeably warm, not hot.
The consistency	Uniformly warm across the bay.	Uneven. The warmth arrives in patches and plumes where vents feed up through the seabed. Most of the swim is cold sea with warm patches in it.
Getting in	Steps down from a boardwalk, or a boat that pulls up to the shore.	Off the stern of the boat into open water, then a swim of roughly 30 to 50 m by community accounts, through cold caldera water, before anything feels warm.
The colour	Clear turquoise with a bit of steam.	Opaque ochre — yellow-green to rust-orange — from iron oxide, plus sulphur and manganese, seeping out of the seabed. You cannot see your own feet.
The smell	Nothing, or something spa-like.	A faint sulphur note. Not strong, not unpleasant, but unmistakably there. It fades within a minute of noticing it.
The bottom	Sand.	Rough volcanic rock, shallowing towards the chapel. Water shoes are a good idea if you have them.
What it does to swimwear	Nothing.	Stains pale fabric orange-brown, and first-hand accounts report it surviving repeated washing. Wear dark, and not the swimsuit you like most.
How long people stay in	An hour of blissful floating.	Ten to twenty minutes for most people. Long enough to find the warm patches, notice the colour, and swim back out.

Temperature figures from tourism publishers, seen 25 August 2026; sea temperatures from Climates to Travel monthly averages. Nobody has published an instrument reading of the springs, so we hedge it and say so.

The temperature, honestly

The figure in circulation is 30 to 35 °C in the bay. It comes from tourism publishers rather than from a thermometer anyone has shown their working on, so hold it loosely.

What matters more is the contrast. Santorini's sea runs about 22 °C in June and about 24.5 °C at the August peak. Warm water arriving at 30-something into a bay of 24 feels like a bath running into a swimming pool: you find it in ribbons, not as a temperature the whole bay has.

Wind, swell and tide all stir it. On a flat morning the warm layer sits and you can feel the line where it starts. On a day with chop, mixing wins and the whole bay reads as mildly tepid. Neither day is wrong, and we cannot tell you in advance which one you have booked.

The colour and the smell

The ochre is iron. Hydrothermal water carrying iron, sulphur and manganese seeps up through vents in the seabed, and the iron oxidises on contact, which puts fine rust-coloured particles into suspension. That is the same chemistry that makes Red Beach red, arriving as a liquid instead of a cliff.

The visual effect is genuinely strange, and it is the part people photograph. Blue caldera water, then a hard-edged plume of orange against it, then the pale chapel of Agios Nikolaos on a black lava shore behind that.

The sulphur smell is faint. Guests notice it in the first thirty seconds and then stop noticing it. It does linger a little on skin and hair, which is what the shower on the way home is for.

The dark swimsuit is not a suggestion

Iron in suspension stains fabric, and first-hand reports describe orange-brown marks that survive repeated laundering. Pale swimwear comes out of that bay a different colour and stays that colour. Wear something dark and old, rinse skin, hair and fabric properly afterwards, and do not wear the swimsuit you like most. This is the single piece of advice on this page that people write to us about later, and we set it out in full in the hot springs swimsuit rule.

Who should sit this one out

Weak swimmers. This is open water, from a boat, with no shallow entry and nothing to stand on for most of the distance. Sources on the stop flag it as unsuitable for weak swimmers, and so do we. There is no shame in staying on deck, and several guests on any given cruise do.

Very young children. Same reason, plus the rough bottom near the shore.

Anyone who wanted a spa. If the picture in your head is a warm pool with a rail and a towel service, this is not that, and no amount of good weather will make it that.

Nothing about the day requires you to get in. There is shade under the bimini, a cold drink, and a view of an active volcano from a boat that is not going anywhere for twenty minutes.

Why it is still worth doing

Because of what it is, rather than what it feels like. You are swimming in the flooded crater of a volcano, in water that is warm because the rock underneath has not finished cooling from the last eruption in 1950. The heat you find in those patches came up through the seabed.

The swim back out is the good bit, oddly. You turn around at the shore and the whole caldera is in front of you. The cliff wall stands two hundred metres high on the far side, with Fira a white line along the top of it. Your own boat sits in water four hundred metres deep.

Go in expecting an ochre swim with warm patches and a strange smell, and it is one of the better twenty minutes of the trip. Go in expecting a hot tub and it is not. That is the whole difference, and it costs nothing to arrange.

Ready when you are

The springs are the day's bonus

On the semi-private day cruise the crater swim at Nea Kameni comes first, around 12:50, and the boat shifts to Palea Kameni whenever the wind lets it hold there. Lunch comes off the grill while you swim. Send us a date and we will tell you what is free.

Check availability & book

Call the harbour office+30 698 977 1888

Common questions

Are the Santorini hot springs actually hot?

No. Warm in patches is the honest description. Published figures put the water at roughly 30 to 35 °C where the springs come up, against a summer sea of 22 to 24.5 °C, and that is a tourism figure rather than an instrument reading. Most of your swim is cold sea.

Do Santorini's hot springs stain your clothes?

Yes, and permanently on pale fabric. The water carries iron oxide in suspension, and first-hand accounts report orange-brown staining that survives repeated washing. Wear dark, old swimwear, rinse everything thoroughly afterwards, and keep the good swimsuit for the beach stops earlier in the day.

What should I wear to the hot springs?

Dark swimwear you do not care about, and water shoes if you have them — the bottom near the shore is rough volcanic rock. Nothing white, nothing new, nothing borrowed. Leave jewellery on the boat; sulphur and silver are not friends, and the water is too opaque to find anything you drop.

How deep is the water at the hot springs?

Deep where the boat lies and shallowing towards the shore, but we cannot give you a figure — no source publishes a measured depth at the anchorage, so we will not invent one. Treat the whole stop as open water: you swim from the stern, and there is nothing to stand on for most of it.

Can you visit the hot springs without a tour?

Not easily. Palea Kameni has no harbour and no road, so arrival is by boat, and the bay is approached by swimming in from a vessel lying off. In practice that means a cruise or a private charter. It is not a place you can drive to and walk into.

Will I be able to join a Catamaran cruise if I get easily seasick and/or cannot swim?

Yes to both, with one caveat. Nothing on board requires you to get in the water, and plenty of guests never do. But the hot springs are open-water only, so if you cannot swim, that is the stop you watch from the deck. For seasickness, take the morning cruise: the wind builds after midday.

Santorini Boat Tour - Water Taxi is a catamaran cruise and water taxi operator based in Fira, Santorini.

Updated August 2026