The Galactic Sea is a celestial location within the much higher area of Skyworld. As its name suggests, much of this area consists of a vast interstellar ocean where constellations are born and held in place. The mystical Galactic Sea embodies the perception of ancient cultures that stars and constellations were symbols of heavenly beings and great powers from above.
In Kid Icarus: Uprising, it serves as the primary location of Chapter 8, where the Three Sacred Treasures were apparently stored away within a constellation, sometime after the events of the original Kid Icarus. Numerous other constellations litter the night skies of the heavens, all of which are held together by physical strings of light. Like Angel Land, the Galactic Sea also has its fair share of bizarre inhabitants, including the dreadful Space Pirates that pilot their ship across the starry ocean. These notorious thieves are often responsible for the disappearance of constellations due to their power and incredible value. Also, deadly Krakens are apparently a notable threat to anything smaller than the beasts themselves, including the aforementioned Space Pirates.
The Galactic Sea has curious properties that is vastly different from regular water that seems to defy real-life physics. It appears to be much more lighter and airy, as Pit can fly through it as if he were in the sky. At the same time, it is dense enough to allow massive creatures like the Kraken to swim through, and the giant Space Pirate Ship to sail across the surface. The water in the Galactic sea also appears to be breathable by air-breathers, as Pit showed no signs of discomfort flying inside it.