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The Grand Underground – Pokémon Brilliant Diamond & Shining Pearl guide

Dig, grab rare Pokémon, build a base, find Diglett and Dugtrio

Dawn and Lucas dig up treasure in the underground in Pokémon Brilliant Diamond and Shining Pearl Image: The Pokémon Company/ILCA Inc
Julia Lee (she/her) is a guides producer, writing guides for games like The Legend of Zelda: Tears of the Kingdom and Genshin Impact. She helped launch the Rift Herald in 2016.

Pokémon Brilliant Diamond and Shining Pearl overhauled the underground feature to add more sprawling caverns, turning it into the Grand Underground. Our Grand Underground guide will explain what to do there, how to build your base, and what rare Pokémon to look for.

Table of contents

How to unlock the Grand Underground

You’ll unlock the Explorer Kit in Eterna City — in fact, you can’t leave the city without getting it and learning how to use it. The old man who hands out the Explorer Kit is in a house next to the Pokémon Center.

How to build a secret base

You can put a base in any wall in the Grand Underground, as long as you have a Digger Drill. After you dig up some treasure for the first time, you can return to the old man in Eterna City, and he’ll give you a Digger Drill to make a base with. Press A on a wall to open up a huge cavern to build your base in.

Once you build your base, you can place any statues that you dig up inside to decorate. These statues increase the rate in which certain Pokémon appear in the Grand Underground.

Statues of Legendary Pokémon have the strongest effect, sparkling statues have a strong effect, and regular statues have an average effect.

The female Pokémon trainer stands in a secret base filled with various statues Image: The Pokémon Company/ILCA Inc via Polygon

How to dig for treasure and statues in the Grand Underground

You’ll see sparkling spots marked on your map. As you get close, you can press R to use your radar, which will pinpoint the location of the treasure on a nearby wall.

Just like the original games, you’ll be able to use the heavy hammer or the delicate pickaxe to dig up treasure in Pokémon Brilliant Diamond and Shining Pearl. Be careful, though: After you dig too much, the wall will collapse.

Use the hammer to find the treasure, and then switch to the pickaxe to carefully dig it out.

How to find Pokémon in the Grand Underground

There are lots of rare Pokémon in the Grand Underground that weren’t in the original games. If you want a Magnemite, Togepi, Ralts, or other Pokémon that were in the Platinum Pokédex, the Grand Underground is your place to look.

These Pokémon are found in their respective biomes, called Pokémon Hideaways. You’ll find Ralts in glittering caves, Togepi in lush springs, and Magnemites in dark caves, for example.

You can find some rare Pokémon early on, but lots of spawns are locked by progress. Even more Pokémon show up after you unlock the National Pokédex.

A Pokémon trainer stands in a Pokémon Hideaway near a Ralts Image: The Pokémon Company/ILCA Inc via Polygon

What do the Diglett and Dugtrio in the Grand Underground do?

As you run around, you’ll notice Diglett and Dugtrio sitting at intersections. When you approach them, they’ll flee, leaving behind some pink glitter. Picking up the glitter fills a gauge on the left side of your screen. Once the gauge is filled, a notice will come up saying “Something good will happen!”

With this bonus, you’re more likely to dig up special green glittering statues from the walls and you’ll have double the chance of finding a Shiny Pokémon underground. This effect wears off after around four minutes.

Update (Nov. 30): We’ve updated this guide with additional information.

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