Tanren Undercity

Tanren Undercity, referred to by players as undercity or sometimes TU, is a city settled under the Tanren region with its own dungeons and currency. Its entrance is located at Tanren's Archaeological Digsite. To access the main entrance of, Rock Smash and Rock Climb are required. If Undercity Catacombs has been completed, players can take a shortcut to Tanren Undercity in cognito.

Central Fork
The Central Fork is the central part of, which is the connection to all the areas in.

Mansion
There is a mansion located northwest in the Central Fork. Trying to enter any of the curtains here gives the message "Perhaps you shouldn't enter this room..." Going to the wall in the middle gives the message "The structuring of this wall seems pretty fragile... Perhaps if you had the right move, it could be broken." Using the move Rock Smash on the wall will open the entrance to the Abandoned Laboratory.

Abandoned Laboratory
The Abandoned Laboratory is accessed from the Tanren Undercity Mansion. This room's only purpose is to change the form of Rotom.

Northern Settlement
The northern settlement is north east from the Central Fork, and commonly thought as the main area in. Here you have access to an Assembly, Kangaskhan's Storage, and a rest house, being Toren's House.{{Clr}

There is also a Purple Kecleon here who runs a shop and sells items for Poké. Notable as this is the only shop in that still uses Poké, as all other shops in  use Ekop - 's exclusive currency.

Dark Market
This is one of the main features in. In this market, you can buy items from various NPCs running booths with different types of items with Ekop.

Sunken Tavern
The Sunken Tavern is a local bar in. You can buy some exclusive drinks in here from Sebastian using Ekop. The active Pokémon has to be level 21 or higher in order to enter.

Night Talons' Base
The headquarters of the Night Talons, one of the two gangs in the undercity, the other gang being the Desert Fangs. Only players with a Minun character ID have access to the Night Talons' Base.

Features located here:
 * Sven the Sharpedo can clean your Sticky or Grimy items.
 * Butch the Scrafty can open your Treasure Boxes for 150 Poké each
 * Rouge the Purrloin can sell you the following items:

Desert Fangs' Base
The headquarters of the Desert Fangs, one of the two gangs in the undercity, the other gang being the Night Talons. Only players with a Plusle character ID have access to the Desert Fangs Base.

Features located here:
 * Dorothy the Gengar can clean your Sticky or Grimy items.
 * Princess the Pangoro can open your Treasure Boxes for 150 Poké each
 * Sam the Zorua (looks like a Krookodile because of Illusion) can sell you the following items:

Dungeons
Tanren Undercity currently has 3 dungeons.
 * Dream Grove
 * Undercity Catacombs
 * Caustic Sewers

Trivia

 * Tanren Undercity was released on September 1st in 2016.
 * The shortcut to in cognito was added on March 19th of 2019.
 * Tanren Undercity was initially supposed to have player combat to represent rivalry between the two gangs, however the idea was scrapped in favor of earlier release.
 * The three NPCs in the mansion are a reference to Fire Emblem Fates.