The Sea Treader's Tunnel Caves is a cavernous system located on Sea Treader's Path, inside the tunnel through which it goes. The caves' entrances can be found both inside (on the walls of the tunnel) and outside (on its top) of the area. It bears many similarites to the Sanctuary Cave in the Deep Sparse Reef.
Like most cave systems, the Tunnel Caves has multiple chambers interconnected by size-varying passages, which house many different types of life forms. Most of its passages are illuminated by Grue Clusters and other decorative plants.