In the Sinnoh region, there are two Pokemon that symbolize the region. They appear in the Sinnoh reigon's myths and old folklore. One is called Dialga and is said to have the power to control time. The other is called Palkia, who is said to have the ability to distort space. The sinister organization called Team Galaxy is trying to rule the region by utilizing these two Pokemons' power. During your adventure to complete your Pokedex and become the Champion, these two Pokemon and Team Galaxy will intertwine into the story and lead you on a fantastic journey across the Sinnoh region.
In Pokemon Diamond, you are a person who goes out on a "Pokemon Adventure" to catch all Pokemon and defeat the Elite Four. But before doing any of this, you must get your starter Pokemon. You will meet many trainers eager to battle you, and even tougher Gym Leaders. The Elite Four and Champion are the hardest trainers in the game. Eventually you will be able to go on WiFi and battle and trade with others. But don't forget your Gameboy Advanced Games. You can still trade with them, only you can't trade any Pokemon back to them. E.G: If you trade a Bulbasaur to Diamond from Leaf Green, you can't trade it back to Leaf Green.
- Trade from older versions! You can trade Pokemon from Pokémon FireRed, LeafGreen, Ruby, Sapphire, and Emerald.
- A whole new Pokémon generation! New Pokemon including Pre-Evolutions, Evolutions of older Pokemon, and a completely new 4th generation of Pokémon.
- Wi-Fi Capability! You will be able to use the Nintendo DS' Wi-Fi capabilities to connect up to 16 players in a union style situation.
- New type combinations! There may not be any new Pokémon types in Pokémon Diamond and Pearl, but do expect to see some new type combinations!
- Return of the Day/Night System! The day and night system from the Gold, Silver, and Crystal versions makes a return, but this time with an additional bonus - Not only will we be experiencing day and night gameplay, but also morning, noon, afternoon, and evening!
- Sprite Differences... When viewing Pokémon in this game, you may notice slight changes between male and female Pokémon. Things such as body patterns, shapes, and sizes will be noticeably different from those of male and female Pokémon.
- A New Professor! A new Pokémon professor will be featured in Diamond and Pearl, that being Professor Nanakamado!
- New Device - The Watch! The watch that your trainer uses will act as the new and improved PokéNav from the Ruby and Sapphire versions, with an additional 20 features! Some of those features being Time Management, Monitoring of Pokémon in the Breeding Center, Type Chart, and many more!
 Hardware Requirements
- Online play via Nintendo Wi-Fi Connection
- Multi-card Multiplayer
- Console-to-DS Link
- DS Card Save
- Voice Support
This game is also known as Pocket Monsters Diamond in Japan.