Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Lahendong Geothermal Spa is situated near Tomohon in North Sulawesi, close to the Lahendong Geothermal Power Plant, one of Indonesia's oldest and most productive geothermal electricity-generating facilities, which harnesses the volcanic energy of the Minahasa Peninsula to power the cities of northern Sulawesi. The nearby Lake Linow is a remarkable tricolor volcanic crater lake whose waters shift between blue, green, and yellow depending on the angle of light and the concentration of dissolved sulfur compounds — a living demonstration of the intense geothermal activity beneath the landscape. The spa draws on this same volcanic energy to deliver naturally heated mineral waters rich in sulfur and trace minerals, offering therapeutic bathing beside one of North Sulawesi's most visually striking geothermal features.
Insider tip — Lahendong is home to one of Indonesia's oldest geothermal power plants, operational since the 1980s, and the spa facilities here were developed alongside the energy infrastructure to showcase sustainable geothermal use. The sulfurous thermal water is piped from production wells at over 150 C and cooled to bathing temperature before reaching the pools, ensuring a consistent 42 C year-round. The facility sits in rolling hills above Manado Bay, with panoramic views of Bunaken Island's coral reefs visible on clear days. Engineers from the power plant often share fascinating insights into geothermal geology with curious visitors.