The Submarine World (海底世界, Kaitei Sekai, Seabed World, aka "Underwater") is an area accessible from the Ghost Garden.
Points of InterestEdit
The Submarine World is a vast ocean floor with many stones and coral. The entrance from Ghost Garden gives you several paths to take. Going north leads you to Underwater Temple. Going between two sandy sticks to your to the top-right leads you to Underwater Settlement.
Going south takes you to a wider looping area. South-west of where you stand is a small sandy house where Oreko lives. Oreko will give you the Diving Helmet Effect once you interact with her. She's usually inside her house, though she can also be found wandering around outside.
Going north-west of where you enter the larger area, there are two symmetrical rows of sandy pillars. Going in between them takes you to a smaller area. South of this area are stairs that lead to the Starry Pier.