Pokémon BDSP: Every Rare Grand Underground Pokémon Spawn

One of the biggest changes incorporated in Pokémon Brilliant Diamond & Shining Pearl was the addition of the Grand Underground, where players can find many of the games' rare Pokémon in the various biomes. The biomes in the Grand Underground are a new feature that was not originally part of Diamond and Pearl, but they're one of the most welcome changes made. The Grand Underground is full of common, rare, and story-locked Pokémon that players are able to find as their journey across Sinnoh progresses.

In order to explore the Grand Underground, players will need to first reach Eterna City and speak with the elderly man in the house next to the Pokémon Center. He will gift players an Explorer Kit, the key item needed to travel to the Grand Underground. Each of the biomes are fixated in the Grand Underground, and using the Explorer Kit in several locations across Sinnoh will further unlock different sections.

Many of the Pokémon in the Grand Underground are tied to unlocking a specific HM, such as Strength, Defog, and Waterfall. It's important to check the Grand Underground biomes every time one of these three HMs are found in order to discover new Pokémon that were previously not part of the experience. Additionally, many of the Pokémon found in the National Pokédex will be found in the Grand Underground after the Sinnoh Pokédex is completed.

Every Rare Grand Underground Pokémon In Brilliant Diamond & Shining Pearl

Pokémon BDSP Explorer Kit Guide: Grand Underground Access Explained

The rare Pokémon below can be found in the Grand Underground at any point throughout Brilliant Diamond and Shining Pearl. They are not locked behind any story progression or HM discovery, allowing players to acquire many Pokémon that were not included in the original Diamond and Pearl before the post-game. Additionally, Brilliant Diamond and Shining Pearl exclusive Pokémon like Elekid and Magby can be caught with items that allow their evolutions, Electabuzz and Magmar, to evolve further into Electivire and Magmortar. Magnemite can also be caught holding a Metal Coat, allowing players to trade both Scyther and Onix early on to receive a Scizor and Steelix. These are the rare Pokémon that can be found in the Grand Underground:

Rare Big Bluff Cavern Pokémon

Scyther (Brilliant Diamond)
Pinsir (Shining Pearl)
Absol

Rare Bogsunk Cavern Pokémon

Lickitung
Gligar (Brilliant Diamond)
Swinub

Rare Dazzling Cave Pokémon

Togepi
Houndoom
Smoochum
Elekid (Brilliant Diamond)
Ralts
Duskull
Absol

Rare Glacial Cavern Pokémon

Magnemite
Swinub
Elekid (Brilliant Diamond)
Teddiursa (Shining Pearl)
Swablu
Snorunt
Glalie

Rare Fountainspring Cave Pokémon

Lickitung
Togepi - This is the only way to find and catch Togepi in Pokémon BDSP before the post-game.
Ralts
Swablu
Gible
Gabite

Rare Grassland Cave Pokémon

Scyther (Brilliant Diamond)
Pinsir (Shining Pearl)
Absol

Rare Icy Cave Pokémon

Magnemite
Swinub
Smoochum
Swablu
Snorunt
Glalie

Rare Riverbank Cave Pokémon

Lickitung
Scyther (Brilliant Diamond)
Pinsir (Shining Pearl)

Rare Rocky Cave Pokémon

Rhyhorn
Gligar (Brilliant Diamond)
Teddiusra (Shining Pearl)

Rare Sandsear Cave Pokémon

Rhyhorn
Houndoom
Magby (Shining Pearl)

Rare Spacious Cave Pokémon

Magnemite
Lickitung
Rhyhorn
Houndoom
Swablu
Absol

Rare Stargleam Cavern Pokémon

Togepi
Houndoom
Smoochum
Elekid (Brilliant Diamond)
Ralts
Duskull
Absol

Rare Still-Water Cavern Pokémon

Lickitung
Scyther (Brilliant Diamond) - Grabbing Scyther early on and trading it for a Scizor is how players can get the best team to start with in the remakes.
Pinsir (Shining Pearl)