A Dungeon is an area, usually underground, that is entered via a ladder or cave mouth. Dungeons are typically more dangerous than the surface.

Generally, caves are also described as 'Dungeons' despite their different appearances. Dungeons are usually accessed via ladders, while caves have more natural entrances. Inside a cave, light shines in through exits to the surface world. Other dungeons often have their walls lined with torches.

The mechanics of entering off-surface areas, excluding caves, allow for the process known as 'Laddering'. When a player leads a creature into a ladder (whether purposely or accidentally), then the creature disappears and does not leave behind a corpse. Some people, such as GMs, frown upon Laddering when it is done on purpose. Accidental Laddering can be a source of frustration when players are attempting to lure creatures elsewhere to fight. However, if a creature is lured into a ladder while there are players on both levels that the ladder reaches, then the creature will not disappear. In addition, creatures spawned by GMs during RTQs will not disappear if Laddered.

The Tracking skill cannot be used in dungeons, as it is too dark. Players cannot use Orbs of Seeing in dungeons. Likewise, players are unable to orb other players who are inside dungeons. However, the light in all dungeons is brighter than the surface world in the dead of night. In dungeons as well as on the surface, a greater amount of creatures spawn during the night hours.

In general, the key to successfull dungeon navigation is larger parties or else thorough knowledge of the dungeon's ins-and-outs. Proper care must be taken to bring enough equipment when embarking on a hunt into a dungeon. Plates, for example, often bring more than one set of armor.