The classic three starting Pokémon from the original Pokémon Red and Blue versions are available in Pokémon Brilliant Diamond and Shining Pearl. You’ll be able to acquire these Pokémon in a specific method, and when you do encounter them, you can add them to your collection. Here’s what you need to do to find Bulbasaur, Charmander, and Squirtle in Pokémon Brilliant Diamond and Shining Pearl.
All three of these Pokémon can be found in the Grand Underground location. You can only find them in their respective regions. For example, you’ll be able to find Bulbasaur in the Grassland Caves or the Sunlight caves. You’ll need to find the specific biome for the three of them. Even then, encountering these Pokémon is not guaranteed.
You’ll only be able to encounter these Pokémon in the Grand Underground once you receive the National PokéDex. After encountering all of the Pokémon in the Sinnoh region PokéDex, you’ll receive the National PokéDex, which means completing the game. You’ll want to treat this as post-game content, so don’t worry about it if you’re exploring the Grand Underground earlier in your Pokémon Brilliant Diamond and Shining Pearl journey. The same goes for many of the Pokémon you usually wouldn’t encounter in the Sinnoh region.
