The Underwater Islands Caves is a cave system that can be found in some of the larger islands in the Underwater Islands biome.
It features upside-down Coral Shell Plates and Cave Crawlers who can be seen falling from the top to bottom. The entrance to the smallest of these caves can be found found right next to the Underwater Islands Wreck. The larger of the caves can be found on a bigger island. These larger caves house more Fauna such as Garryfish and Bonesharks, as well as more materials. There are four entrances to this cave and three to the smaller one.