Top best answers to the question «Where to find the underwater cave in pokemon ruby»
The Seafloor Cavern (Japanese: 海底洞窟 Seabed Cavern) is a location in Hoenn, deep beneath the water of Route 128. After surfacing inside the cave, there is a maze of tunnels to the deepest part, where the super-ancient Pokémon resides. In order to reach it, the player must use Surf and Dive.
Seafloor Cavern is a hidden area in southeastern Hoenn. It can only be reached by diving into an underwater trench in Route 128. The entrance is at the south part of the trench. Resurface to reach the entrance of the cave.