Jupiter's moon Callisto is very likely an ocean world

Recent expanded analysis much more strongly suggests that Callisto hosts a subsurface ocean.

Salt deposits found on a asteroid Ryugu

A team of researchers has found evidence of salt minerals in samples recovered from Ryugu during the initial phase of Japan's Hayabusa2 mission.

Trench-like features on Uranus's moon Ariel may be windows to its interior

Last year, a study proposed that deposits of carbon dioxide ice and other carbon-bearing molecules on Uranus's moon Ariel likely originated from chemical processes inside the moon—possibly even from a subsurface ocean.

Uranus' moon Ariel may have a hidden ocean

New research has revealed that the surface of Uranus’ moon Ariel is coated with a significant amount of carbon dioxide ice, particularly on its trailing hemisphere, which always faces away from the moon’s direction of orbital motion. 

Webb Finds Evidence of Hydrothermal Processes in Interiors of Eris and Makemake

The icy dwarf planets Eris and Makemake have surfaces bearing methane ice of unknown origin. The two planets may have warm oceans. 

Saturn's moon Mimas may have vast, hidden ocean

Saturn's small, crater-covered moon Mimas may have a vast ocean under its thick icy surface, according to a new paper.

Two moons of Uranus may have active oceans, new study finds

Scientists now believe Miranda and Ariel, the smallest and second-smallest of Uranus’s five major moons, could be expelling vapour plumes - which on other moons in the solar system are thought to come from subsurface oceans.