The Lythoin Caves was an underground tunnel system, similar to Morrow Caverns. It is right beneath Darkwater Cove. Ratchet was thrown into Lythoin Caves, when entering Captain Darkwater's treasure room. He had to fight a pirate army, Pythors, and Sprocket in order to escape the caves and save Talwyn.
- Ratchet & Clank Future: Quest for Booty (first appearance)