The Underground zones or Moon Mines are caves, tunnels or paths that are interlaced in the form of underground labyrinths around them that are located in the standard terrestrial area of Hanazuki's Moon. Its first and only appearance was in "Underground Escape".
The underground areas become a kind of tunnel road, which connects with others as they are managed by an anthill, although now it is more likely that the heart of the underground areas is the place where Depriva resides, who has the responsibility of that many people end up trapped there.
Its inhabitants so far have been very few in total, since there only live a couple of green worms and Depriva, not counting Emerald Hemka and Raspberry Hemka who managed to escape.
- In "Underground Escape", Depriva is responsible for creating the quicksands, and it is revealed that the way to reach the underground zone is absorbed by said sands, which is somewhat inconsistent with the episode where the sands first appeared, "Slow Sand Rises". In that episode, Hanazuki tried to save Pink Hemka, trapped in quicksand, and the other Hemkas found the pit where Pink Hemka was trapped. But the pit was totally solid and there was no path to the lunar mines.