Editor’s Note
This guide outlines the initial steps to access the Underground Caves in Pokémon Brilliant Diamond and Shining Pearl, starting with reaching Eterna City. For the complete walkthrough, including the crucial conversation needed to obtain the Explorer Kit, please continue reading the full article.
To unlock access to the Underground Caves in Pokémon Brilliant Diamond and Shining Pearl, the first thing you must do is progress far enough in the story to reach Eterna City, where you earn the game’s second badge (reaching here will take you approximately 5 hours).
Once in Eterna City, you must head to the house to the right of the Pokémon Center.
The character will give you the Explorer Kit, a key item that allows you to access the Underground Caves whenever you want by equipping it.
From then on, you can travel to Sinnoh’s underground world from any town or route (but not from inside buildings or caves). Furthermore, if you continue talking to the old man from now on, he will propose various missions to you that serve to unlock the Drill and essentially learn the mechanics of this aspect of the game.
Below we share the image of the complete map of the Underground Caves in Pokémon Brilliant Diamond and Shining Pearl, where you can consult absolutely all the locations of the revealed dens, the positions of vendors, Pokémon healing spots, and secret base expansions.
The map image was created thanks to PokeJungle and the Reddit user Nakfu1.
Originally, your Underground Caves map will be unexplored, and a bunch of question marks will appear on the Pokémon dens. However, when you visit these dens for the first time, their information will be revealed to make future exploration easier.
Keep in mind that the Underground Caves map is divided into 6 large labyrinthine sections and roughly coincides with the overworld map of Sinnoh. This means that to travel to some parts of the underground, you will have to descend into it from specific zones in the Sinnoh region.
– Main Underground Zone: Accessible from the vast majority of zones and routes in Sinnoh (these are the largest and most connected tunnels in the underground).
– Central Underground Zone: Accessible from Celestic Town.
– Northwest Underground Zone: Accessible from Snowpoint City (adjacent routes) and Fullmoon Island.
– Northeast Underground Zone: Accessible from the Battle Zone, Survival Area, Resort Area, and adjacent routes.
– Southwest Underground Zone: Accessible from Twinleaf Town, Canalave City, Hearthome City, and adjacent routes.
– Southeast Underground Zone: Accessible from Pastoria City and adjacent routes.
The Underground Caves have several special characteristics. The most important is the presence of Pokémon dens, with their different biomes, where you will find wild Pokémon running around that you can capture (we give you details on this below).
However, there are also a series of other options available in the underground, which we review below as a summary for clarity:
– Treasure Excavation: You can excavate at shiny spots in the cave hallways (veins) to find items such as gems, fossils, slates, statues, evolutionary stones, and more.
– Secret Base: With the Drill given to you by the Underground Man, you can also create a Secret Base on any wall in the underground. In this place, you can place Pokémon statues to increase their appearance rate.
– Energy Bonus: In the underground tunnels, you will encounter Diglett and Dugtrio that leave glowing energy. If you collect it and accumulate 40 points, you can receive a bonus for the appearance of Shiny Pokémon that lasts approximately 4 minutes.
– Vendors: In the caves, you will also find NPC vendors who, in exchange for gems, can sell you a series of valuable items, such as TMs, statues, gems, and more.
– Pokémon Healing: In the tunnels, you can also find NPCs who will be happy to heal your Pokémon to restore their HP and PP.
In addition to all this, it must not be forgotten that traveling through the Underground Caves can be done accompanied by other players. Every time you use the Explorer Kit to descend into the caves, you can choose whether you want to do it solo, but also if you want to access multiplayer functions, either through local communication or online (a Nintendo Switch Online subscription is required).