Loutra Kythnos Hot Springs (Agioi Anargyroi and Kakavos)

Which springs this page covers

The slug names two springs, Agioi Anargyroi and Kakavos. Several Greek places share those saint names, but the two together point to one place: the village of Loutra on the north-east coast of Kythnos in the western Cyclades. The island’s old name, Thermia, comes from them. The Agioi Anargyroi spring rises inside the historic hydrotherapy centre; Kakavos rises about 50 m away and flows into the sea. Both are officially recognised thermal natural resources in the Government Gazette.

What to expect

Loutra is a small seaside village (81 permanent residents in 2011) with a marina, a fishing shelter, a sandy bay and a row of tavernas and cafés along the front. You come here for the beach pool, because the spa itself is shut.

The beach pool

Where the Kakavos water reaches the shore, people have stacked rocks to make a small pool at the water’s edge. Hot spring water runs in from one side and the sea washes in from the other. Near the inflow it is too hot to sit in for long; a little further toward the sea it cools down. One local description from 2024 gives about 104-113°F40-45°C for the mixed water, and you move a metre or two to find what suits you. It is free, unstaffed and open at any hour. Early morning and sunset are the favourite times, when the bay is quiet.

This is an informal spot, not a managed bathing site. A January 2026 parliamentary question put it plainly: the springs are officially unused, and visitors use only the point where Kakavos flows into the sea.

The springs

• Kakavos: about 125.6°F52°C at the source, iron-bearing, with iodine, bromide and sodium chloride and weak natural radioactivity.
• Agioi Anargyroi: about 100.4°F38°C (sources range from 96.8°F to 100.4°F36°C to 38°C, 97-100°F36-38°C), salty and heavily mineralised. It feeds the closed spa building and you cannot reach it.

The closed hydrotherapy centre

The neoclassical bathhouse is the reason Loutra is on the map. A first vaulted pool was built at the Agioi Anargyroi source in 1782. After Greek independence, the royal architect Christian Hansen drew up plans in 1836, his assistant Laurent finished the work, and the building was completed in 1857. King Otto and Queen Amalia visited. It is often called the first organised spa in modern Greece, and Ernst Ziller later made changes to it.

The state tourism organisation ran a Xenia hotel here from 1951. The hotel closed in 1999, and bath attendants kept the baths going informally in summer for a few more years. Older guides that describe marble tubs, 20-minute sessions and summer opening hours date from that period. Do not plan on them.

The whole complex is a listed monument. It passed to the state asset fund (HRADF) in 2013 and in 2022 was conceded through ETAD to a private investor for 99 years, for €2.8 million. In February 2024 the company Xenia Kythnos applied to restore it as a 5-star hotel with a thermal centre, and in January 2026 the ministry approved the plot for special tourism use. As of May 2026 the project was still in permitting, the springs’ official recognition was awaiting renewal, and the only work done on site was fencing and a scale model. Expect fences around the building.

Getting there

• Ferry: Boats from Lavrio take about 1.5 to 2.5 hours, with several sailings a week all year. A weekly boat from Piraeus takes about 3 hours. All dock at Merichas, on the west coast.
• By road: Loutra is about 11 km (6.8 miles) from Merichas and about 5 km (3.1 miles) from Chora, the island capital. The drive takes around 20 minutes from Merichas.
• Bus: A local bus runs Merichas-Messaria-Loutra. Timetables change by season, so ask at the port.
• On foot: The rock pool is on the main beach in front of the village, a short walk from wherever you park.

When to go

The pool is usable all year, because the spring flows all year.

• May, June, September and October are the best months: warm enough to swim, cool enough to enjoy hot water, and fewer people.
• July and August are peak season on the island, and a pool this small fills quickly by day. Go at dawn.
• Winter soaks are possible on calm days. In rough weather, waves wash over the rocks and cool the pool.

Rules and etiquette

There are no posted rules for the rock pool because it is not an official facility.

• Swimsuits: This is a village beach in front of tavernas. Wear a swimsuit.
• Share it: The pool holds only a few people. Move along after a while if others are waiting.
• No soap: Do not wash with soap or shampoo in the pool or the outflow.
• Leave the rocks: Do not rebuild or dam the pool.
• Respect the fence: The spa building is private, listed and fenced. Do not climb in.

Where to stay nearby

• Loutra has rooms, suites and small hotels along the bay and the road to Agia Irini, plus tavernas and cafés on the front.
• Chora, 5 km (3.1 miles) away, has more rooms and the island’s main village life.
• Merichas, the port, is the most practical base if you are relying on ferries and buses.

Safety notes

• Scalding water: At the inflow the water is close to 125.6°F52°C. Test with your hand and keep children away from the hot end.
• Untreated water: Nobody tests this pool. Keep your head above water and do not drink it.
• Rocks and waves: The stones are slippery, and swell can push cold water and sand into the pool without warning.
• Health: If you have heart or blood pressure problems, keep soaks short.

Nearby stops worth adding

From Loutra a dirt road and then a path lead to Kastro tis Orias (Kefalokastro), the medieval capital of Kythnos, abandoned after the Ottomans destroyed it in 1570. The neighbouring bays of Agia Irini, Schinari and Maroula are a short walk along the coast. Kythnos also has a network of marked hiking trails if you want more than a beach day.