There are 4 ocean planets and 11 ocean moons in our solar system. All ocean worlds have subsurface saltwater oceans except for Io, which as a subsurface magma ocean. Earth of course has surface oceans.
Moon of Jupiter
Asteroid Belt dwarf
Moon of Saturn
Home world
Kuiper Belt dwarf
Moon of Uranus
Moon of Neptune
A number of ocean worlds past the snow line (between Mars and Jupiter) are "active" where their subsurface ocean punches through the crust and forms active cryovolcanoes or cryogeysers. Note that Ganymede and Europa have oceans that exceed the volume of Earth's ocean. That's a lot of water.
The Earth is the cradle of humanity, but mankind cannot stay in the cradle forever.
- Konstantin Tsiolkovsky
