Nea Kameni and Palea Kameni — the "Burnt Islands" — are the volcano's newest work, pushed up over the last two thousand years and still gently exhaling. On every Santorini volcano boat tour we run, the boat noses into the little cove of Agios Nikolaos on Palea Kameni, where volcanic vents warm the sea to a bath-like 30–35 °C and stain it a startling rust-orange with dissolved iron. You swim from the boat through progressively warmer water until you're floating in the volcano's own jacuzzi, with a tiny white chapel watching from the rocks.
Does the boat stop on the volcano itself?
No — and it's worth knowing before you book anything on the island. Our cruises sail close along Nea Kameni's black lava flows (near enough to smell the faint sulphur on a still day) but don't dock for the crater hike; that's a separate walking excursion on dedicated ferry boats, a hot, shadeless 30-minute climb we'd honestly rank below the swim. The nea kameni hot springs experience from a catamaran is the comfortable version: you get the geology, the story, and the warm water — without the queue up a gravel path in beach sandals.
The dark swimsuit rule
The palea kameni hot springs are mineral springs in the most literal sense: iron and sulphur compounds hang in the water, and they will leave a faint orange signature on light-coloured lycra that no hotel laundry fully undoes. Wear a dark swimsuit for this stop — it's the single most useful packing tip on this island, and the reason it's printed on our packing list in bold.
Photo tip
The colour gradient is the shot: shoot from the deck looking down as swimmers cross the line where blue sea turns rust. On the sunset cruise the low light turns that boundary almost metallic. In the water itself, keep the phone in a floating case — the springs have collected several sacrifices.
The honest caveat
The warm patch is a cove, not a swimming pool: nearest the vents it's genuinely warm, at the edges just pleasantly less cold, and after rain the mineral cloudiness thickens. Also, the seafloor near the chapel is soft volcanic mud — some guests love wearing it (it's a spa thing, apparently), others prefer to float and abstain. Both are correct.
