The Sinnoh region represents the fourth generation of Pokémon, and despite all the new features and the Hokkaido-like setting, the core mechanic of version exclusives remains. That means there are Pokémon unique to Diamond that you cannot get in Pearl, and vice versa. If you’ve gotta catch ’em all, you will need to trade with someone.
Pokémon Diamond, Pearl, and Platinum – Version Exclusives
