Which moon of Saturn has a subsurface ocean and geysers?

The Saturnian moon with a subsurface ocean and geysers is Enceladus. This small, icy moon ejects plumes of water vapor and ice particles through fractures near its south pole.

Cassini first observed the plumes in 2005, transforming Enceladus from an otherwise intriguing moon into one of the Solar System’s most scientifically important worlds. Gravity measurements later provided evidence for a liquid ocean beneath the global ice shell. The ocean is salty and appears to interact with a rocky seafloor, where hydrothermal activity may provide energy.

The geysers also feed Saturn’s diffuse E ring. Some plume particles fall back onto Enceladus, creating fresh snow, while others escape into orbit. Cassini detected salts, silica-rich grains, organic molecules, ammonia, and molecular hydrogen in or around the plume material—ingredients that make the moon a major target in the search for potentially habitable environments.

Europa is also famous for an underground ocean, but it is a moon of Jupiter. Titan is Saturn’s largest moon and has lakes of liquid hydrocarbons on its surface, while Mimas is smaller and heavily cratered.