Planet 4546B is a fictional exoplanet featured in the video game Subnautica. It is located in a distant star system and is primarily covered by vast oceans, making it a unique underwater environment. The planet is known for its diverse marine life, including various species of flora and fauna, some of which are bioluminescent. The atmosphere of Planet 4546B is breathable for humans, but it contains high levels of oxygen and nitrogen. The planet's surface is dotted with underwater structures and alien technology, hinting at a rich history. Players explore this world while managing resources and surviving against the challenges it presents.