- For tips on navigating the Dungeon, see Guide:Surviving in the Dungeon.
The Dungeon is a vast underground brick labyrinth that is generated on world creation, either on the far right or left of the map, and contains unique enemies whose spawn rates increase the deeper a player travels. It begins at an above-ground entrance structure resembling a castle, and extends down to near-Underworld depths. A single Dungeon is generated in each world. Accessing the Dungeon requires first defeating Skeletron (see Access below). The Dungeon can appear in one of three Dungeon Brick colors, and with one or more Dungeon Brick Wall patterns, which the game randomly picks when the world is first created.
The Dungeon contains a dense assortment of unique furniture and Mechanisms that can be retrieved by the player (using a Pickaxe) for later use: Several Dart Traps are Wired to Pressure Plates, providing an extra hazard to players. One of these is sometimes found above-ground at the Dungeon's entrance. Chain Lanterns are found wired to Switches, which the player can toggle on and off. The bound Mechanic is also found here, and is freed when spoken to.
There are several locked Golden Chests containing both Dungeon-only loot and standard underground loot. A Golden Key is required to open each of these, which can be obtained from Pots, Dungeon Slimes, and from other Chests in the Dungeon. Locked Biome Chests are also present, which can only be opened using materials available after Plantera is defeated.
After Plantera is defeated, the Dungeon spawns new, more powerful enemies, which offer access to new items. Not all enemies spawn in all Dungeons: The particular background wall type generated for a particular Dungeon, as well as the corresponding Faction Flags scattered around, determine which post-Plantera enemies spawn there (see below).
In order to gain unrestricted access to the Dungeon, Skeletron must first be defeated. Skeletron is summoned by speaking to the Old Man, who guards the Dungeon entrance, at Night. The "curse" option will display, which will turn the Old Man into Skeletron when clicked. Speaking to the Old Man during the Day will not allow you to fight Skeletron.
The Dungeon can be entered but not fully explored before Skeletron is defeated. Traveling below zero depth in the Dungeon before Skeletron has been defeated will trigger multiple Dungeon Guardians which will generally kill any player with a single hit. If you can manage to kill a Dungeon Guardian, it will drop a rare item. However, killing a Dungeon Guardian does not grant you access to the Dungeon.
You can tell if the requirements to spawn Dungeon Guardians are met if the music changes to the unique Dungeon track, or if you have a Depth Meter equipped that reads 0 or a negative number. Dungeon entrances are located at varying heights, but are always some distance above zero depth, making their entrance structures and 1-2 screens of depth generally safe from Guardians.
 Hardmode post-Plantera Dungeon
When you enter a Dungeon after defeating Plantera during Hardmode in the PC version, new more difficult enemies spawn. They will be much stronger than the regular enemies, and there is even one enemy that deals more damage than Skeletron Prime. The player may remember finding four Biome Chests earlier, which require Biome Keys to open. It's recommended that the Hardmode dungeon only be tackled once a player has Hallowed armor or better.
The particular post-Plantera enemies that spawn in a Dungeon area depend on its background wall type. A single Dungeon can contain multiple background wall types in different sections, or just one type. Whether a Dungeon contains different types can only be determined by exploring the Dungeon. A player will often need to generate more than one world, and defeat Plantera in each (along with the Wall of Flesh and the 3 Mechanical Bosses that make Plantera available) in order to encounter all post-Plantera enemy types.
Bone Lee appears in all Dungeon types, and drops the following:
Dungeon Spirits appear in all Dungeon types, spawning randomly on the death on any enemy with 100 or more health.
- The Dungeon will always be on the side of the map opposite the Jungle. If you're looking for the dungeon and run into a Jungle, turn around and go the other way.
- A player is considered to be in the Dungeon if they're below the depth of -4 feet and standing in front of any naturally-placed Wall, if there are at least 250 Dungeon Bricks on screen, except dirt walls.
- You may also farm wires from the dungeon by using a wire cutter.
- Most Dungeons, regardless of their visible background walls, have tiled walls behind their foreground blocks. After Plantera has been defeated, mining the blocks can expose the tiled walls, potentially allowing enemies associated with those walls to spawn.
- 220.127.116.11: Fixed bug where hardmode dungeon casters would shoot more than 1 projectile in multiplayer.
- 1.2.4: The Dungeon (as well as the Underworld) has more new Furniture generated at world creation.
- 1.2.3: Heart Crystals no longer spawn in the dungeon.
- 18.104.22.168: Now only generates hardmode enemies after Plantera is defeated.
- 1.1: Now generated with traps and light sources wired to switches.
- Pre-Release: Introduced.
| Game mechanics|
|Attack Speed • Breath meter • Buffs • By hand • Consumable • Crafting station • Critical hit • Damage • Data IDs • Day/Night • Death • Debuffs • Defense • Difficulty • Environment • Event • Fall Damage • Game controls • Ghost • Health • Inventory • Knockback • Lighting mode • Mana • Map Size • Minimap • Minions • Modifier • Moon • Music • NPC drops • NPC Spawning • Placement • Player stats • Rarity • Spawn • Storage • Use time • Value • Velocity|